diff --git a/figs/inkscape/introduction_id31_station_detector.svg b/figs/inkscape/introduction_id31_station_detector.svg index 3852e6c..c7bbff3 100644 --- a/figs/inkscape/introduction_id31_station_detector.svg +++ b/figs/inkscape/introduction_id31_station_detector.svg @@ -4,11 +4,11 @@ + inkscape:current-layer="layer1" /> + transform="translate(-51.184196,-44.297839)"> Detector , ultra thick}}; + + % Blocks + \node[draw, fill=lightblue, align=center, label={[mylabel, text width=8.0cm] Dynamical Models}, minimum height = 4.5cm, text width = 8.0cm] (model) at (0, 0) {}; + + \node[myblock, fill=lightgreen, label={[mylabel] Disturbances}, left = 3 of model.west] (dist) {}; + \node[myblock, fill=lightgreen, label={[mylabel] Micro Station}, below = 2pt of dist] (mustation) {}; + \node[myblock, fill=lightgreen, label={[mylabel] Nano Hexapod}, above = 2pt of dist] (nanohexapod) {}; + + \node[myblock, fill=lightyellow, label={[mylabel] Mech. Design}, above = 1 of model.north] (mechanical) {}; + \node[myblock, fill=lightyellow, label={[mylabel] Instrumentation}, left = 2pt of mechanical] (instrumentation) {}; + \node[myblock, fill=lightyellow, label={[mylabel] FEM}, right = 2pt of mechanical] (fem) {}; + + \node[myblock, fill=lightred, label={[mylabel] Test Benches}, right = 3 of model.east] (testbenches) {}; + \node[myblock, fill=lightred, label={[mylabel] Assembly}, above = 2pt of testbenches] (mounting) {}; + \node[myblock, fill=lightred, label={[mylabel] Implementation}, below = 2pt of testbenches] (implementation) {}; + + % Text + \node[anchor=south, above, text width=8cm, align=left] at (model.south) {Extensive use of models for:\begin{itemize}[noitemsep,topsep=5pt]\item Extraction of transfer functions \\ \item Choice of appropriate control architecture \\ \item Tuning of control laws \\ \item Closed loop simulations \\ \item Noise budgets / Evaluation of performances \\ \item Sensibility to parameters / disturbances\end{itemize}\centerline{Models are at the core the mecatronic approach!}}; + + \node[mymodel] at (mustation.south) {Multiple stages \\ Complex dynamics}; + \node[mymodel] at (dist.south) {Ground motion \\ Position errors}; + \node[mymodel] at (nanohexapod.south) {Different concepts \\ Sensors, Actuators}; + + \node[mymodel] at (instrumentation.south) {Sensors, Actuators \\ Electronics}; + \node[mymodel] at (mechanical.south) {Proper integration \\ Ease of assembly}; + \node[mymodel] at (fem.south) {Optimize key parts: \\ Joints, Plates, APA}; + + \node[mymodel] at (mounting.south) {Struts \\ Nano-Hexapod}; + \node[mymodel] at (testbenches.south) {Instrumentation \\ APA, Struts}; + \node[mymodel] at (implementation.south) {Control tests \\ Micro Station}; + + % Links + \draw[->] (dist.east) -- node[above, midway]{{\small Measurements}} node[below,midway]{{\small Spectral Analysis}} (dist.east-|model.west); + \draw[->] (mustation.east) -- node[above, midway]{{\small Measurements}} node[below, midway]{{\small CAD Model}} (mustation.east-|model.west); + + \draw[->] ($(nanohexapod.east-|model.west)-(0, 0.15)$) -- node[below, midway]{{\small Optimization}} ($(nanohexapod.east)-(0, 0.15)$); + \draw[<-] ($(nanohexapod.east-|model.west)+(0, 0.15)$) -- node[above, midway]{{\small Model}} ($(nanohexapod.east)+(0, 0.15)$); + + \draw[->] ($(fem.south|-model.north)+(0.15, 0)$) -- node[right, midway]{{\small Specif.}} ($(fem.south)+(0.15,0)$); + \draw[<-] ($(fem.south|-model.north)-(0.15, 0)$) -- node[left, midway,align=right]{{\small Super}\\{\small Element}} ($(fem.south)-(0.15,0)$); + + \draw[->] ($(mechanical.south|-model.north)+(0.15, 0)$) -- node[right, midway]{{\small Specif.}} ($(mechanical.south)+(0.15,0)$); + \draw[<-] ($(mechanical.south|-model.north)-(0.15, 0)$) -- node[left, midway,align=right]{{\small CAD}\\{\small model}} ($(mechanical.south)-(0.15,0)$); + + \draw[->] ($(instrumentation.south|-model.north)+(0.15, 0)$) -- node[right, midway]{{\small Specif.}} ($(instrumentation.south)+(0.15,0)$); + \draw[<-] ($(instrumentation.south|-model.north)-(0.15, 0)$) -- node[left, midway]{{\small Model}} ($(instrumentation.south)-(0.15,0)$); + + \draw[->] ($(mounting.west-|model.east)+(0, 0.15)$) -- node[above, midway]{{\small Requirements}} ($(mounting.west)+(0, 0.15)$); + \draw[<-] ($(mounting.west-|model.east)-(0, 0.15)$) -- node[below, midway]{{\small Model refinement}} ($(mounting.west)-(0, 0.15)$); + + \draw[->] ($(testbenches.west-|model.east)+(0, 0.15)$) -- node[above, midway]{{\small Control Laws}} ($(testbenches.west)+(0, 0.15)$); + \draw[<-] ($(testbenches.west-|model.east)-(0, 0.15)$) -- node[below, midway]{{\small Model refinement}} ($(testbenches.west)-(0, 0.15)$); + + \draw[->] ($(implementation.west-|model.east)+(0, 0.15)$) -- node[above, midway]{{\small Control Laws}} ($(implementation.west)+(0, 0.15)$); + \draw[<-] ($(implementation.west-|model.east)-(0, 0.15)$) -- node[below, midway]{{\small Model refinement}} ($(implementation.west)-(0, 0.15)$); + + % Main steps + \node[font=\bfseries, rotate=90, anchor=south, above] (conceptual_phase_node) at (dist.west) {1 - Conceptual Phase}; + \node[font=\bfseries, above] (detailed_phase_node) at (mechanical.north) {2 - Detail Design Phase}; + \node[font=\bfseries, rotate=-90, anchor=south, above] (implementation_phase_node) at (testbenches.east) {3 - Experimental Phase}; + \begin{scope}[on background layer] + \node[fit={(conceptual_phase_node.north|-nanohexapod.north) (mustation.south east)}, fill=lightgreen!50!white, draw, inner sep=2pt] (conceptual_phase) {}; + \node[fit={(detailed_phase_node.north-|instrumentation.west) (fem.south east)}, fill=lightyellow!50!white, draw, inner sep=2pt] (detailed_phase) {}; + \node[fit={(implementation_phase_node.north|-mounting.north) (implementation.south west)}, fill=lightred!50!white, draw, inner sep=2pt] (implementation_phase) {}; + % \node[above left] at (dob.south east) {DOB}; + \end{scope} + + % Between main steps + \draw[mystep, postaction={decorate,decoration={raise=1ex,text along path,text align=center,text={Concept Validation}}}] (conceptual_phase.north) to[out=90, in=180] (detailed_phase.west); + \draw[mystep, postaction={decorate,decoration={raise=1ex,text along path,text align=center,text={Procurement}}}] (detailed_phase.east) to[out=0, in=90] (implementation_phase.north); + + % % Inside Model + % \node[inner sep=1pt, outer sep=6pt, anchor=north west, draw, fill=white, thin] (multibodymodel) at ($(model.north west) - (0, 0.5)$) + % {\includegraphics[width=5.6cm]{simscape_nano_hexapod.png}}; + + % \node[inner sep=1pt, outer sep=6pt, anchor=south west, draw, fill=white, thin] (simscape) at (model.south west) + % {\includegraphics[width=5.6cm]{simscape_picture.jpg}}; + + % % Feedback Model + % \node[inner sep=3pt, outer sep=6pt, anchor=north east, draw, fill=white, thin] (simscape_sim) at ($(model.north east) - (0, 0.5)$) + % {\includegraphics[width=3.6cm]{simscape_simulations.pdf}}; + + % % FeedBack + % \node[inner sep=3pt, outer sep=6pt, anchor=south east, draw, fill=white, thin] (feedback) at (model.south east) + % {\includegraphics[width=3.6cm]{classical_feedback_small.pdf}}; +\end{tikzpicture} +#+end_src + +#+name: fig:introduction_nass_mechatronics_approach +#+caption: Overview of the mechatronic approach used for the Nano-Active-Stabilization-System +#+attr_latex: :width \linewidth +#+RESULTS: +[[file:figs/introduction_nass_mechatronics_approach.png]] + +*** Stewart platform + +#+name: fig:introduction_stewart_platform +#+caption: The Stewart Platform. Architecutre is shown in (\subref{fig:introduction_stewart_architecture}). Change of pose induce by change of strut length is shown in (\subref{fig:introduction_stewart_pose}) +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_stewart_architecture} Stewart Platform Architecture} +#+attr_latex: :options {0.49\textwidth} +#+begin_subfigure +#+attr_latex: :scale 0.8 +[[file:figs/introduction_stewart_architecture.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_stewart_pose} Change of mobile platform pose} +#+attr_latex: :options {0.49\textwidth} +#+begin_subfigure +#+attr_latex: :scale 0.8 +[[file:figs/introduction_stewart_pose.png]] +#+end_subfigure +#+end_figure + +*** Models (lumped mass - multi-body - FEM) + +#+begin_src latex :file introduction_model_lumped.pdf :results file raw silent +\begin{tikzpicture} + % ==================== + % Parameters + % ==================== + \def\massw{2.2} % Width of the masses + \def\massh{0.8} % Height of the masses + \def\spaceh{1.2} % Height of the springs/dampers + \def\dispw{0.4} % Width of the dashed line for the displacement + \def\disph{0.4} % Height of the arrow for the displacements + \def\bracs{0.05} % Brace spacing vertically + \def\brach{-12pt} % Brace shift horizontaly + \def\fsensh{0.2} % Height of the force sensor + \def\velsize{0.2} % Size of the velocity sensor + % ==================== + + + % ==================== + % Floor + % ==================== + \draw (-0.5*\massw, 0) -- (0.5*\massw, 0); + % \draw[dashed] (0.5*\massw, 0) -- ++(\dispw, 0); + % \draw[->, draw=colorred] (0.5*\massw+0.5*\dispw, 0) -- ++(0, \disph) node[right, color=colorred]{$x_{f}$}; + % ==================== + + % ==================== + % Granite + \begin{scope}[shift={(0, 0)}] + % Mass + \draw[fill=white] (-0.5*\massw, \spaceh) rectangle (0.5*\massw, \spaceh+\massh) node[pos=0.5]{$m_{1}$}; + + % Spring, Damper, and Actuator + \draw[spring] (-0.3*\massw, 0) -- (-0.3*\massw, \spaceh) node[midway, left=0.1]{$k_{1}$}; + \draw[damper] ( 0.3*\massw, 0) -- ( 0.3*\massw, \spaceh) node[midway, left=0.2]{$c_{1}$}; + + % Displacement + \draw[dashed] (0.5*\massw, \spaceh+\massh) -- ++(\dispw, 0); + \draw[->] (0.5*\massw+0.5*\dispw, \spaceh+\massh) -- ++(0, \disph) node[right]{$x_{1}$}; + \end{scope} + % ==================== + + + % ==================== + % Stages + \begin{scope}[shift={(0, \spaceh+\massh)}] + % Mass + \draw[fill=white] (-0.5*\massw, \spaceh) rectangle (0.5*\massw, \spaceh+\massh) node[pos=0.5]{$m_{2}$}; + + % Spring, Damper, and Actuator + \draw[spring] (-0.4*\massw, 0) -- (-0.4*\massw, \spaceh) node[midway, left=0.1]{$k_{1}$}; + \draw[damper] (0, 0) -- ( 0, \spaceh) node[midway, left=0.2]{$c_{2}$}; + \draw[actuator={0.45}{0.2}{black}] ( 0.4*\massw, 0) -- (0.4*\massw, \spaceh) node[midway, left=0.1]{$F$}; + + % Displacement + \draw[dashed] (0.5*\massw, \spaceh+\massh) -- ++(\dispw, 0); + \draw[->] (0.5*\massw+0.5*\dispw, \spaceh+\massh) -- ++(0, \disph) node[right]{$x_{2}$}; + \end{scope} + % ==================== +\end{tikzpicture} +#+end_src + +#+name: fig:introduction_models +#+caption: Types of models used when using a mechatronics approach. (\subref{fig:introduction_model_lumped}) (\subref{fig:introduction_model_multibody}) (\subref{fig:introduction_model_fem}) +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_model_lumped} Mass-Spring-Damper model} +#+attr_latex: :options {0.3\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_model_lumped.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_model_multibody} Multi-Body model} +#+attr_latex: :options {0.39\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.9\linewidth +[[file:figs/introduction_model_multibody.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_model_fem} Finite Element Model} +#+attr_latex: :options {0.3\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.9\linewidth +[[file:figs/introduction_model_fem.jpg]] +#+end_subfigure +#+end_figure + +*** Closed-Loop +#+begin_src latex :file introduction_closed_loop.pdf +\begin{tikzpicture} + \node[block] (controller) {Controller}; + \node[block, right = 1 of controller] (driver) {Driver}; + \node[block, right = 1 of driver] (actuator) {Actuator}; + \node[block, right = 1 of actuator, align=center] (system) {Mechanical\\System}; + \node[block, right = 1 of system] (sensor) {Sensor}; + + % Connections and labels + \draw[->] (controller.east) node[above right]{$u$} -- (driver.west); + \draw[->] (driver.east) -- (actuator.west); + \draw[->] (actuator.east) -- (system.west); + \draw[->] (system.east) --node[midway, above]{$y$} (sensor.west); + \draw[->] (sensor.east) -- ++(1.2, 0); + \draw[->] ($(sensor.east)+(0.6,0)$)node[branch]{}node[above]{$y_m$} -- ++(0, -2.0) -| (controller.south); + + \draw[<-] (controller.west) -- ++(-1.0, 0) node[above right]{$r$}; + \draw[<-] (driver.north) -- ++(0, 1.2) node[below right, align=left]{$d_u$}; + \draw[<-] (system.north) -- ++(0, 1.2) node[below right, align=left]{$d_y$}; + \draw[<-] (sensor.north) -- ++(0, 1.2) node[below right, align=left](sensornoise){$n$}; + + % Plant + \begin{scope}[on background layer] + \node[fit={(driver.south west) (sensornoise.north -| sensor.east)}, fill=black!20!white, draw, dashed, inner sep=8pt] (plant) {}; + \node[below] at (plant.north) {\textbf{Plant}}; + \end{scope} + + \draw[->, dashed] ($(plant.south) + (0, -0.3)$) arc (90:-90:0.3) -- ++(-2.5, 0) arc (-90:-270:0.3); + \node[left] at ($(plant.south) + (0, -0.6)$) {Feedback Loop} +\end{tikzpicture} +#+end_src + +#+RESULTS: +#+name: fig:introduction_closed_loop +#+caption: Block diagram of a typical feedback control architecture +[[file:figs/introduction_closed_loop.png]] + + +*** Dynamic Error Budgeting + +#+name: fig:introduction_deb +#+caption: Tools used for the dynamic error budgeting. First the Power Spectral Density can be compared (\subref{fig:introduction_psd}). The cumulative power spectrum is shown in (\subref{fig:introduction_cps}). To compare the effectivness of different strategies, the cumulative power spectrum can be compared (\subref{fig:introduction_cps_cl}) +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_psd} Power Spectral Density - Open Loop} +#+attr_latex: :options {0.33\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.9\linewidth +[[file:figs/introduction_psd.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_cps} Cumulative Power Spectrum - Open Loop} +#+attr_latex: :options {0.33\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.9\linewidth +[[file:figs/introduction_cps.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_cps_cl} Cumulative Power Spectrum - Comparison} +#+attr_latex: :options {0.33\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.9\linewidth +[[file:figs/introduction_cps_cl.png]] +#+end_subfigure +#+end_figure + +*** Active Damping + +#+name: fig:introduction_damping +#+caption: Uniaxial vibration isolation strategies. Integral force feedback (\subref{fig:introduction_damping_iff}) and "sky-hook" damping (\subref{fig:introduction_damping_skyhook}). +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_damping_iff} Integral Force Feedback} +#+attr_latex: :options {0.49\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_damping_iff.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_damping_skyhook} "Sky-hook" Damping} +#+attr_latex: :options {0.49\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_damping_skyhook.png]] +#+end_subfigure +#+end_figure + +*** Decentralized Control + +#+name: fig:introduction_control_decentralized +#+caption: Decentralized control. Example of decentralized force feedback (\subref{fig:introduction_control_decentralized_schematic}), only three struts are shown for simplicity. Equivalent block diagram (\subref{fig:introduction_control_decentralized_diagram}), the controller is then diagonal. +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_control_decentralized_schematic} Decentralized Control applied on Stewart platform} +#+attr_latex: :options {0.54\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.95\linewidth +[[file:figs/introduction_control_decentralized_schematic.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_control_decentralized_diagram} Equivalent block diagram} +#+attr_latex: :options {0.45\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.95\linewidth +[[file:figs/introduction_control_decentralized_diagram.png]] +#+end_subfigure +#+end_figure +*** Centralized Control + +#+name: fig:introduction_control_centralized +#+caption: Two centralized control strategies. Express the position error in the frame of the struts and design one controller for each strut (\subref{fig:introduction_control_centralized_struts}). Design one controller for each direction, and then map the forces and torques to each struts (\subref{fig:introduction_control_centralized_cartesian}). +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_control_centralized_struts} Control in the frame of the struts} +#+attr_latex: :options {0.95\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_control_centralized_struts.png]] +#+end_subfigure + +\bigskip +#+attr_latex: :caption \subcaption{\label{fig:introduction_control_centralized_cartesian} Control in the cartesian frame} +#+attr_latex: :options {0.95\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_control_centralized_cartesian.png]] +#+end_subfigure +#+end_figure + +*** MIMO vs Decoupling Control + +#+name: fig:introduction_control_mimo_vs_decoupling +#+caption: Two strategies to control a multi-inputs-multi-outputs system. Use of a multivariable controller (\subref{fig:introduction_control_mimo}), or first decouple the plant with matrices, and then designing several single-input-single-output controllers (\subref{fig:introduction_control_decoupling}) +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_control_mimo} Multivariable Control} +#+attr_latex: :options {0.33\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_control_mimo.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_control_decoupling} Decoupling Control} +#+attr_latex: :options {0.66\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_control_decoupling.png]] +#+end_subfigure +#+end_figure + +*** Multiple Sensor Control + +#+name: fig:introduction_control_multiple_sensors +#+caption: Different control strategies when using multiple sensors. High Authority Control / Low Authority Control (\subref{fig:introduction_architecture_hac_lac}). Sensor Fusion (\subref{fig:introduction_architecture_sensor_fusion}). Two-Sensor Control (\subref{fig:introduction_architecture_two_sensor_control}) +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_architecture_hac_lac} HAC-LAC} +#+attr_latex: :options {0.48\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_architecture_hac_lac.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_architecture_two_sensor_control} Two Sensor Control} +#+attr_latex: :options {0.48\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_architecture_two_sensor_control.png]] +#+end_subfigure + +\bigskip +#+attr_latex: :caption \subcaption{\label{fig:introduction_architecture_sensor_fusion} Sensor Fusion} +#+attr_latex: :options {0.95\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_architecture_sensor_fusion.png]] +#+end_subfigure +#+end_figure + +*** Mechanical bearing and Flexure stages + +#+name: fig:introduction_translation_stage +#+caption: A classical translation stage composed of: a rotary motor and possibly reduction gears (in blue), a mechanism to transform the rotary motion to a translation (here a lead screw in green), a guiding mechanism (here linear rails and bearings in red). The mobile platform (in yellow) can then translate with respect to the fixed base. +[[file:figs/introduction_translation_stage.png]] + +#+name: fig:introduction_flexure_stage +#+caption: A simple flexure stage +[[file:figs/introduction_flexure_stage.png]] + +** Unused Tables +*** End-Stations with Online metrology + +#+name: tab:introduction_online_metrology +#+caption: End-Station integrating accurate online metrology systems. For all the examples, the sample used are in the micron scale. +#+attr_latex: :environment tabularx :width 1.0\linewidth :align cccccc +#+attr_latex: :center t :booktabs t :font \scriptsize +| *Architecture* | *Metrology* | *Usage* | *Institute* | *References* | +|-------------------------------------+-------------------+------------------+-------------+--------------------------------------------| +| Sample | 3 Capacitive | Post processing | NSLS | cite:&wang12_autom_marker_full_field_hard | +| XYZ Stage | $D_yD_zR_x$ | | (X8C) | Figure ref:fig:introduction_stages_wang | +| *Metrology Ring* | | | | | +| Spindle | | | | | +|-------------------------------------+-------------------+------------------+-------------+--------------------------------------------| +| *Ball-lens retroreflector* / Sample | 3 interferometers | Characterization | PETRA III | [[cite:&schroer17_ptynam;&schropp20_ptynam]] | +| XYZ piezo stage ($100\,\mu m$) | $D_yD_z$ | | (P06) | Figure ref:fig:introduction_stages_schroer | +| Spindle ($180\,\text{deg}$) | | | | | +|-------------------------------------+-------------------+------------------+-------------+--------------------------------------------| +| *Metrology Ring* / Sample | 2 interferometers | Detector | NSLS | [[cite:&xu23_high_nsls_ii]] | +| Spindle | $D_yD_z$ | triggering | (HRX) | | +| XYZ piezo stage | | | | | + +*** End stations with Feedback control based on online-metrology + +#+name: tab:introduction_active_stations +#+caption: End-Stations with integrated feedback loops based on online metrology. Stages used for static positioning are ommited for readability. Stages used for feedback are indicated in bold font. +#+attr_latex: :environment tabularx :width 1.0\linewidth :align cccccc +#+attr_latex: :center t :booktabs t :font \scriptsize +| *Architecture* | *Metrology* | *Stroke* | *Bandwidth* | *Institute* | *References* | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Mirror / Sample | 3 Interferometers | | n/a | APS | [[cite:&nazaretski15_pushin_limit]] | +| *XYZ piezo motors* | $D_xD_yD_z$ | $D_xD_yD_z: 3\,\text{mm}$ | | | Figure ref:fig:introduction_stages_nazaretski | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Metrology Ring / Sample | 12 Capacitive | light | 10 Hz | ESRF | [[cite:&villar18_nanop_esrf_id16a_nano_imagin_beaml]] | +| Spindle | $D_xD_yD_zR_xR_y$ | $R_z: 180\,\text{deg}$ | | (ID16a) | Figure ref:fig:introduction_stages_villar | +| *Piezo Hexapod* | | $D_xD_yD_z: 50\,\mu m$ | | | | +| | | $R_x R_y: 500\,\mu \text{rad}$ | | | | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Spherical Reference / Sample | 5 Interferometers | light | n/a | PSI | [[cite:&holler17_omny_pin_versat_sampl_holder;&holler18_omny_tomog_nano_cryo_stage]] | +| Spindle | $D_yD_zR_x$ | $R_z: 365\,\text{deg}$ | | (OMNY) | | +| *Piezo Tripod* | | $D_xD_yD_z: 400\,\mu m$ | | | | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Cylindrical Reference / Sample | 5 Interferometers | light | n/a | Soleil | [[cite:&stankevic17_inter_charac_rotat_stages_x_ray_nanot;&engblom18_nanop_resul]] | +| Spindle | $D_xD_yD_zR_xR_y$ | $R_z: 360\,\text{deg}$ | | | | +| *Stacked XYZ linear motors* | | $D_xD_yD_z: 400\,\mu m$ | | | | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Metrology Ring / Sample | 3 Interferometers | up to 500g | n/a | NSLS | [[cite:&nazaretski22_new_kirkp_baez_based_scann]] | +| Spindle | $D_xD_yD_z$ | $R_z: 360\,\text{deg}$ | | (SRX) | | +| *XYZ piezo* | | $D_xD_yD_z: 100\,\mu m$ | | | | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Mirrors / Sample | 3 Interferometers | up to 350g | 100 Hz | Diamond | [[cite:&kelly22_delta_robot_long_travel_nano]] | +| *Parallel XYZ voice coil* | $D_xD_yD_z$ | $D_xD_yD_z: 3\,\text{mm}$ | | (I14) | | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Retroreflectors / Samples | 3 Interferometers | light | 100 Hz | LNLS | [[cite:&geraldes23_sapot_carnaub_sirius_lnls]] | +| *Parallel XYZ voice coil* | $D_xD_yD_z$ | $D_yD_z: 3\,\text{mm}$ | | (Carnauba) | | +| Spindle | | $R_z: \pm 110\,\text{deg}$ | | | | +|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| +| Sample | 6 Interferometers | *up to 50kg* | | ESRF | [[cite:&dehaeze18_sampl_stabil_for_tomog_exper;&dehaeze21_mechat_approac_devel_nano_activ_stabil_system]] | +| *Hexapod* | $D_xD_yD_zR_xR_y$ | | | (ID31) | Figure ref:fig:introduction_nass_concept_schematic | +| Spindle | | $R_z : 360\,\text{deg}$ | | | | +| Ry | | $R_y : \pm 3\,\text{deg}$ | | | | +| Ty | | $D_y : \pm 5\,\text{mm}$ | | | | + +*** Two stage control + +#+name: tab:introduction_dual_stages +#+caption: For each example, interferometers are used as the measured stage position (and signal feedback for the short stroke actuator). +#+attr_latex: :environment tabularx :width \linewidth :align ccccc +#+attr_latex: :center t :booktabs t :font \scriptsize +| *DoF* | *Long Stroke* | *Short Stroke* | *Bandwidth* | *Metrology* | *References* | +|--------+-----------------------------------------------------+----------------------------+------------------------+-----------------------+-------------------------------------------------------------------------------| +| X | Servo motor, leadscrew, rotary encoder | PZT, flexure (10um) | n/a | Interferometer, X | cite:&pahk01_ultra_precis_posit_system_servo_motor | +| X,Y | 2 axis, linear motor | 2 PZT, flexures | n/a | Interferometers, XY | cite:&chassagne07_nano_posit_system_with_sub | +| X,Y,Rz | X, linear motor, linear guides | 4 VCM (1mm), air bearing | 85Hz | Interferometers, XYRz | cite:&choi08_desig_contr_nanop_xy_theta_scann | +| X | 1 axis, DC motor, feedscrew, rotary encoder (25mm) | 1 PZT (17um), flexures | 2000Hz | Interferometer, X | cite:&buice09_desig_evaluat_singl_axis_precis | +| X,Y,Rz | 1 axis, ballscrew, rotary motor | 3 piezo, flexure | 3 PID, $\approx 1\,Hz$ | Interferometers, XYRz | cite:&liu10_desig_contr_long_travel_nano_posit_stage | +| X | 1 axis, Servo motor, ball screw (300mm) | 1 VCM, air bearing (5mm) | n/a | Interferometer, X | cite:&shinno11_newly_devel_long_range_posit | +| X | 1 axis, VCM, flexure (10mm) | APA, flexure (15um) | PID, $\approx 1\,Hz$ | Interferometer, X | cite:&xu12_desig_devel_flexur_based_dual | +| X | 1 axis X, ballscrew, stepper | 1 piezo stack Y | n/a | Capacitive, Y | cite:&ting11_contr_desig_high_frequen_cuttin | +| X,Y | 2 axis, air bearing, linear motors (500mm), encoder | 4 VCM XYRz (3mm) | n/a | Interferometer, XYRz | cite:&okazaki12_dual_servo_mechan_stage_contin_posit | +| X | 1 axis, linear motor | 1 VCM | 800Hz | Interferometer, X | cite:&ito13_high_precis_posit_system_using;&ito15_low_stiff_dual_stage_actuat | +| X | stepper motor, ballscrew (300mm) | PZT (16um) | 70Hz | Linear Encoder, X | cite:&kim13_desig_contr_singl_stage_dual | +| X,Y | 2 axis stepper (100mm), encoder | 4 PZT (130um) | $\approx 10\,Hz$ | Interferometers, XY | cite:&wu13_desig | +| X | 1 axis, linear motor (10mm), encoder | 1 VCM | 130 Hz | Interferometer, X | cite:&zhu17_flexur_based_paral_actuat_dual | +| X,Y | XY stepper motor (100mm), ballscrew, encoder | 2 PZT (100um) + capacitive | $\approx 10\,Hz$ | Combine both | cite:&wang17_devel_contr_long_strok_precis_stage | + +** DONE [#A] Make a paragraph about Mechatronics approach / DEB +CLOSED: [2025-04-17 Thu 16:52] +**** Predicting performances using models + + +**** Dynamic Error Budgeting + +cite:jabben07_mechat + +** DONE [#A] Review of two stage control +CLOSED: [2025-04-17 Thu 16:49] + +- *Could be interesting to show that 6DoF active compensation of two-stage control is quite new* + +*Articles*: +- [X] cite:&xu12_desig_devel_flexur_based_dual +- [X] cite:&pahk01_ultra_precis_posit_system_servo_motor +- [X] cite:&kobayashi03_phase_stabil_servo_contr_dual + disk drive +- [X] cite:&michellod06_strat_contr_dual_nano_system_singl_metrol +- [X] cite:&woody06_desig_perfor_dual_drive_system +- [X] cite:&chassagne07_nano_posit_system_with_sub +- [X] cite:&schitter08_dual +- [X] cite:&buice09_desig_evaluat_singl_axis_precis +- [X] cite:&liu10_desig_contr_long_travel_nano_posit_stage +- [X] cite:&ting11_contr_desig_high_frequen_cuttin +- [X] cite:&okazaki12_dual_servo_mechan_stage_contin_posit +- [X] cite:&ito13_high_precis_posit_system_using +- [X] cite:&kim13_desig_contr_singl_stage_dual +- [X] cite:&wu13_desig +- [X] cite:&ito15_low_stiff_dual_stage_actuat +- [X] cite:&zhu17_flexur_based_paral_actuat_dual +- [X] cite:&wang17_devel_contr_long_strok_precis_stage +- [X] cite:&yun20_inves_two_stage_vibrat_suppr + Stewart platform used as vibration isolation + +*Books*: +- [ ] cite:&yamaguchi13_advan_high_perfor_motion_contr_mechat_system +- [ ] cite:&qingsong16_desig_implem_large_range_compl_microp_system +- [ ] cite:&du19_multi_actuat_system_contr + +*To read in details*: +- [X] cite:&choi08_desig_contr_nanop_xy_theta_scann + *top* +- [X] [[cite:&buice09_desig_evaluat_singl_axis_precis]] +- [X] cite:&shinno11_newly_devel_long_range_posit +- [X] cite:&okazaki12_dual_servo_mechan_stage_contin_posit +- [X] cite:&shan15_contr_review + *Good review* + #+begin_quote + Since the proposal of the first dual-actuation stage composed of a combination of ball screw drives and a rotary motor for the long-stroke stage and piezoelectric actuators for the fine stage in 1988, many studies have been performed. +When the coarse actuator and fine actuator are combined, some problems are solved and some other problems develop, such as stability, response speed, and friction. + #+end_quote + #+begin_quote + The motion range of the piezoelectric actuator (short stroke) will at least compensate the motion error of the VCM (long-stroke) and the bandwidth of the piezoelectric actuator is higher than that of the VCM to compensate the system error. + #+end_quote +- [X] cite:&okyay16_mechat_desig_dynam_contr_metrol + *Good review* + #+begin_quote + The alternative, sliding contact bearings are limited to 2-10 [μm] motion resolution, due to stick-slip motion [[cite:&slocum92_precis_machin_desig]], hence they are not preferred. +Stick-slip occurs due to the difference between static and dynamic coefficients of friction in such bearings, which results in an impact-like disturbance in the control system during motion reversal. + #+end_quote +- [X] cite:&kong18_vibrat_isolat_dual_stage_actuat + *Only found example of dual stage with hexapod*. But only for vibration isolation + #+begin_quote + The coarse stage is usually actuated by VCMs or other linear motors, and the fine stage is usually actuated by piezoelectric actuators or VCMs. + #+end_quote + ** DONE [#C] Complete list of Synchrotrons CLOSED: [2024-05-14 Tue 17:28] @@ -928,6 +1506,11 @@ Only recently, high bandwidth (100Hz) have been reported with the use of voice c | *Parallel XYZ voice coil stage* / Sample | 3 interferometers[fn:2]: $XYZ$ | 100Hz | XYZ: 3mm | up to 350g | Diamond, I14 | [[cite:&kelly22_delta_robot_long_travel_nano]] | | Rz / *Parallel XYZ voice coil stage* / Sample | 3 interferometers[fn:1]: $XYZ$ | 100Hz | YZ: 3mm, Rz: +-110deg | light | LNLS, CARNAUBA | [[cite:&geraldes23_sapot_carnaub_sirius_lnls]] | +[fn:4]Capacitive sensors from Fogale Sensors +[fn:3]Attocube FPS3010 Fabry-Pérot interferometers +[fn:2]Attocube IDS3010 Fabry-Pérot interferometers +[fn:1]PicoScale SmarAct Michelson interferometers + ** DONE [#C] Review about Stewart platform control CLOSED: [2024-05-29 Wed 16:16] @@ -1047,7 +1630,8 @@ Bandwidth is rarely specified Same table for nano positioning stages without integrated metrology? -** TODO [#B] Talk about performance specifications +** DONE [#B] Talk about performance specifications +CLOSED: [2025-04-17 Thu 15:30] Smallest beamsize: 200nm x 100nm - Goal: Keep the PoI in the beam: peak to peak errors of 200nm in Dy and 100nm in Dz @@ -1055,128 +1639,74 @@ Smallest beamsize: 200nm x 100nm - Ry error <1.7urad, 250nrad RMS What is the filtering? +I don't think we consider any filtering as high frame rate might be used -** TODO [#B] Add table to compare Stewart platforms +** CANC [#B] Add table to compare Stewart platforms +CLOSED: [2025-04-16 Wed 19:12] +- State "CANC" from "TODO" [2025-04-16 Wed 19:12] [[file:~/Cloud/work-projects/ID31-NASS/matlab/stewart-simscape/org/bibliography.org]] -** TODO [#C] Review of two stage control +** DONE [#A] Modifications based on discussion with Christophe +CLOSED: [2025-04-17 Thu 15:30] -*Articles*: -- [X] cite:&xu12_desig_devel_flexur_based_dual -- [X] cite:&pahk01_ultra_precis_posit_system_servo_motor -- [X] cite:&kobayashi03_phase_stabil_servo_contr_dual - disk drive -- [X] cite:&michellod06_strat_contr_dual_nano_system_singl_metrol -- [X] cite:&woody06_desig_perfor_dual_drive_system -- [X] cite:&chassagne07_nano_posit_system_with_sub -- [X] cite:&schitter08_dual -- [X] cite:&buice09_desig_evaluat_singl_axis_precis -- [X] cite:&liu10_desig_contr_long_travel_nano_posit_stage -- [X] cite:&ting11_contr_desig_high_frequen_cuttin -- [X] cite:&okazaki12_dual_servo_mechan_stage_contin_posit -- [X] cite:&ito13_high_precis_posit_system_using -- [X] cite:&kim13_desig_contr_singl_stage_dual -- [X] cite:&wu13_desig -- [X] cite:&ito15_low_stiff_dual_stage_actuat -- [X] cite:&zhu17_flexur_based_paral_actuat_dual -- [X] cite:&wang17_devel_contr_long_strok_precis_stage -- [X] cite:&yun20_inves_two_stage_vibrat_suppr - Stewart platform used as vibration isolation - -*Books*: -- [ ] cite:&yamaguchi13_advan_high_perfor_motion_contr_mechat_system -- [ ] cite:&qingsong16_desig_implem_large_range_compl_microp_system -- [ ] cite:&du19_multi_actuat_system_contr - -*To read in details*: -- [X] cite:&choi08_desig_contr_nanop_xy_theta_scann - *top* -- [X] [[cite:&buice09_desig_evaluat_singl_axis_precis]] -- [X] cite:&shinno11_newly_devel_long_range_posit -- [X] cite:&okazaki12_dual_servo_mechan_stage_contin_posit -- [X] cite:&shan15_contr_review - *Good review* - #+begin_quote - Since the proposal of the first dual-actuation stage composed of a combination of ball screw drives and a rotary motor for the long-stroke stage and piezoelectric actuators for the fine stage in 1988, many studies have been performed. -When the coarse actuator and fine actuator are combined, some problems are solved and some other problems develop, such as stability, response speed, and friction. - #+end_quote - #+begin_quote - The motion range of the piezoelectric actuator (short stroke) will at least compensate the motion error of the VCM (long-stroke) and the bandwidth of the piezoelectric actuator is higher than that of the VCM to compensate the system error. - #+end_quote -- [X] cite:&okyay16_mechat_desig_dynam_contr_metrol - *Good review* - #+begin_quote - The alternative, sliding contact bearings are limited to 2-10 [μm] motion resolution, due to stick-slip motion [[cite:&slocum92_precis_machin_desig]], hence they are not preferred. -Stick-slip occurs due to the difference between static and dynamic coefficients of friction in such bearings, which results in an impact-like disturbance in the control system during motion reversal. - #+end_quote -- [X] cite:&kong18_vibrat_isolat_dual_stage_actuat - *Only found example of dual stage with hexapod*. But only for vibration isolation - #+begin_quote - The coarse stage is usually actuated by VCMs or other linear motors, and the fine stage is usually actuated by piezoelectric actuators or VCMs. - #+end_quote - - -#+name: tab:introduction_dual_stages -#+caption: For each example, interferometers are used as the measured stage position (and signal feedback for the short stroke actuator). -#+attr_latex: :environment tabularx :width \linewidth :align ccccc -#+attr_latex: :center t :booktabs t :font \scriptsize -| *DoF* | *Long Stroke* | *Short Stroke* | *Bandwidth* | *Metrology* | *References* | -|--------+-----------------------------------------------------+----------------------------+------------------------+-----------------------+-------------------------------------------------------------------------------| -| X | Servo motor, leadscrew, rotary encoder | PZT, flexure (10um) | n/a | Interferometer, X | cite:&pahk01_ultra_precis_posit_system_servo_motor | -| X,Y | 2 axis, linear motor | 2 PZT, flexures | n/a | Interferometers, XY | cite:&chassagne07_nano_posit_system_with_sub | -| X,Y,Rz | X, linear motor, linear guides | 4 VCM (1mm), air bearing | 85Hz | Interferometers, XYRz | cite:&choi08_desig_contr_nanop_xy_theta_scann | -| X | 1 axis, DC motor, feedscrew, rotary encoder (25mm) | 1 PZT (17um), flexures | 2000Hz | Interferometer, X | cite:&buice09_desig_evaluat_singl_axis_precis | -| X,Y,Rz | 1 axis, ballscrew, rotary motor | 3 piezo, flexure | 3 PID, $\approx 1\,Hz$ | Interferometers, XYRz | cite:&liu10_desig_contr_long_travel_nano_posit_stage | -| X | 1 axis, Servo motor, ball screw (300mm) | 1 VCM, air bearing (5mm) | n/a | Interferometer, X | cite:&shinno11_newly_devel_long_range_posit | -| X | 1 axis, VCM, flexure (10mm) | APA, flexure (15um) | PID, $\approx 1\,Hz$ | Interferometer, X | cite:&xu12_desig_devel_flexur_based_dual | -| X | 1 axis X, ballscrew, stepper | 1 piezo stack Y | n/a | Capacitive, Y | cite:&ting11_contr_desig_high_frequen_cuttin | -| X,Y | 2 axis, air bearing, linear motors (500mm), encoder | 4 VCM XYRz (3mm) | n/a | Interferometer, XYRz | cite:&okazaki12_dual_servo_mechan_stage_contin_posit | -| X | 1 axis, linear motor | 1 VCM | 800Hz | Interferometer, X | cite:&ito13_high_precis_posit_system_using;&ito15_low_stiff_dual_stage_actuat | -| X | stepper motor, ballscrew (300mm) | PZT (16um) | 70Hz | Linear Encoder, X | cite:&kim13_desig_contr_singl_stage_dual | -| X,Y | 2 axis stepper (100mm), encoder | 4 PZT (130um) | $\approx 10\,Hz$ | Interferometers, XY | cite:&wu13_desig | -| X | 1 axis, linear motor (10mm), encoder | 1 VCM | 130 Hz | Interferometer, X | cite:&zhu17_flexur_based_paral_actuat_dual | -| X,Y | XY stepper motor (100mm), ballscrew, encoder | 2 PZT (100um) + capacitive | $\approx 10\,Hz$ | Combine both | cite:&wang17_devel_contr_long_strok_precis_stage | - -** TODO [#A] Modifications based on discussion with Christophe - -- [ ] Evolution of precision of instrument over time? +- [X] Evolution of precision of instrument over time? + Difficult to do - [ ] Tables can be put in annex if necessary - [-] Review of literature should not be in introduction: - [X] Stewart platform in chapter 2 - [X] Control architecture for Stewart platforms: maybe in chapter 1 when talking about control? *yes* - [ ] Mechatronics approach just before/in the outline -** TODO [#A] Important point of payload mass +** DONE [#A] Important point of payload mass +CLOSED: [2025-04-17 Thu 16:27] Because the payload's mass can be higher than the mass of the micro-hexapod mass, the coupling becomes very high. -For most of end-stations, the top stages (for small stroke scans) is quite light, and the sample as well. -This way, the short stroke stage dynamics is not coupled to the dynamics of the stages bellow. - -In the NASS case, the payload's mass may be one order of magnitude heavier than the mass of the long stroke top platform. -This induce large coupling between stages and is a challenge. - +** DONE [#C] Maybe remove the footnotes that may not be important +CLOSED: [2025-04-17 Thu 16:48] * Context of this thesis ** Synchrotron Radiation Facilities +:PROPERTIES: +:UNNUMBERED: t +:END: **** Accelerating electrons to produce intense X-ray -- Explain what is a Synchrotron: light source -- Say how many there are in the world (~50). The main ones are shown in Figure ref:fig:introduction_synchrotrons. +- Explain what is a Synchrotron: + - A particle (electrons) accelerator light source + - Electrons produce very bright light, called synchrotron light + - This very intense light, in the X-ray regime, is then used to study matter. +- There are around 70 Synchrotron light sources in the world + Some of the main ones are shown in Figure ref:fig:introduction_synchrotrons. + This shows how useful the produced light is for the scientific community. #+name: fig:introduction_synchrotrons #+caption: Major synchrotron radiation facilities in the world. 3rd generation Synchrotrons are shown in blue. Planned upgrades to 4th generation are shown in green, and 4th generation Synchrotrons in operation are shown in red. #+attr_latex: :width \linewidth [[file:figs/introduction_synchrotrons.png]] -- Electron part: LINAC, Booster, Storage Ring ref:fig:introduction_esrf_schematic -- Synchrotron radiation: Insertion device / Bending magnet -- Many beamlines (large diversity in terms of instrumentation and science) -- Science that can be performed: - - structural biology, structure of materials, matter at extreme, ... +There are two main parts in the Synchrotron: +- The accelerator where electrons are accelerated close to the speed of light + The generation of the synchrotron light is made by placing magnetic fields on the electron beam path. + These are called Insertion device or Bending magnet. +- The beamlines where the intense X-ray beam is used to study matter **** The European Synchrotron Radiation Facility +European Synchrotron Radiation Facility (ESRF): +- Joint research facility situated in Grenoble, France +- supported by 19 countries +- Opened for user operation in 1994: World's first third generation synchrotron (i.e. integrating ) + +Accelerator (Schematically shown in Figure ref:fig:introduction_esrf_schematic): +- The Linear accelerator: where the electrons are +- Booster: electrons are accelerated closed to the speed of light +- Storage Ring: where the electrons are stored. Circumference of 844m. + +Then, there are over 40 beamlines all around the storage ring: +- Large diversity in terms of instrumentation and science +- Science that can be performed: structural biology, structure of materials, matter at extreme, ... + #+name: fig:instroduction_esrf #+caption: Schematic (\subref{fig:introduction_esrf_schematic}) and picture (\subref{fig:introduction_esrf_picture}) of the European Synchrotron Radiation Facility #+attr_latex: :options [htbp] @@ -1195,29 +1725,35 @@ This induce large coupling between stages and is a challenge. #+end_subfigure #+end_figure -**** 3rd and 4th generation Synchrotrons +**** 3rd and 4th Generation Light Sources -Brilliance: figure of merit for synchrotron - -- 4th generation light sources [[cite:&raimondi21_commis_hybrid_multib_achrom_lattic]] +ESRF–EBS (Extremely Brilliant Source): [[cite:&raimondi21_commis_hybrid_multib_achrom_lattic]] +- In August 2020, after a 20-month shutdown, the ESRF is the first fourth-generation +- It uses a new storage ring concept that allows increased brilliance and coherence of the X-ray beams + The brilliance (also called brightness) is figure of merit for Synchrotron. + It corresponds to ... + 100x increase with the EBS +- This new beam offers many new scientific opportunities, but also creates many engineering challenges. #+name: fig:introduction_moore_law_brillance #+caption: Evolution of the peak brilliance (expressed in $\text{photons}/s/mm^2/mrad^2/0.1\%BW$) of synchrotron radiation facilities. Note the vertical logarithmic scale. [[file:figs/introduction_moore_law_brillance.png]] ** The ID31 ESRF Beamline +:PROPERTIES: +:UNNUMBERED: t +:END: **** Beamline Layout -- General layout: source (insertion device), optical hutches (OH1, OH2), experimental hutch (EH) -- Beamline layout (OH Figure ref:fig:introduction_id31_oh, EH ref:fig:introduction_id31_cad) - All these optical instruments are used to "shape" the x-ray beam as wanted (monochromatic, wanted size, focused, etc...) -- ID31 and Micro Station (Figure ref:fig:introduction_id31_cad) - Check https://www.esrf.fr/UsersAndScience/Experiments/StructMaterials/ID31 - https://www.wayforlight.eu/beamline/23244 -- X-ray beam + detectors + sample stage -- Focusing optics -- Optical schematic with: source, lens, sample and detector. - Explain that what is the most important is the relative position between the sample and the lens. +Beamline "layout" refers to the series of elements located in between the "light source" and the sample. +- Each beamline start with a "white" beam, which is just generated by the insertion device (i.e. the "source"). + This beam has very high power (typically above kW), and is typically not directly used on the sample. +- Instead, the beam goes through a series of optical elements (absorbers, mirrors, slits, monochromators, etc.) to filter and "shape" the x-ray beam as wanted. + These elements are located in several Optical Hutches as shown in Figure Figure ref:fig:introduction_id31_oh +- Then, there is the Experimental Hutch (Figure ref:fig:introduction_id31_cad). + For some experiments (that are especially of interest here), focusing optics are used. + The sample is located on the sample stage (also called "end-station"), as is used to position the sample with respect to the x-ray. + Detectors are used to capture the image formed by the x-ray going through the sample - Explain the XYZ frame for all the thesis (ESRF convention: X: x-ray, Z gravity up) #+name: fig:introduction_id31_oh @@ -1240,90 +1776,65 @@ Brilliance: figure of merit for synchrotron #+end_subfigure #+end_figure -#+begin_src latex :file id31_microstation_picture.pdf -\begin{tikzpicture} - \node[inner sep=0pt, anchor=south west] (photo) at (0,0) - {\includegraphics[width=0.39\textwidth]{/home/thomas/Cloud/documents/reports/phd-thesis/figs/exp_setup_photo.png}}; - - \coordinate[] (aheight) at (photo.north west); - \coordinate[] (awidth) at (photo.south east); - - \coordinate[] (granite) at ($0.1*(aheight)+0.1*(awidth)$); - \coordinate[] (trans) at ($0.5*(aheight)+0.4*(awidth)$); - \coordinate[] (tilt) at ($0.65*(aheight)+0.75*(awidth)$); - \coordinate[] (hexapod) at ($0.7*(aheight)+0.5*(awidth)$); - \coordinate[] (sample) at ($0.9*(aheight)+0.55*(awidth)$); - - % Granite - \node[labelc] at (granite) {1}; - % Translation stage - \node[labelc] at (trans) {2}; - % Tilt Stage - \node[labelc] at (tilt) {3}; - % Micro-Hexapod - \node[labelc] at (hexapod) {4}; - % Sample - \node[labelc] at (sample) {5}; - - % Axis - \begin{scope}[shift={($0.07*(aheight)+0.87*(awidth)$)}] - \draw[->] (0, 0) -- ++(55:0.7) node[above] {$y$}; - \draw[->] (0, 0) -- ++(90:0.9) node[left] {$z$}; - \draw[->] (0, 0) -- ++(-20:0.7) node[above] {$x$}; - \end{scope} -\end{tikzpicture} -#+end_src - -#+name: fig:introduction_id31_cad -#+caption: CAD view of the ID31 Experimal Hutch (EH). There are typically four main elements: the focusing optics in yellow, the sample stage in green, the sample itself in purple and the detector in blue. All these elements are fixed to the same granite. -#+attr_latex: :width 0.8\linewidth -[[file:figs/introduction_id31_station_detector.png]] **** Positioning End Station: The Micro-Station -Micro-Station: -- DoF with strokes: Ty, Ry, Rz, Hexapod -- Experiments: tomography, reflectivity, truncation rod, ... - Make a table to explain the different "experiments" -- Explain how it is used (positioning, scans), what it does. But not about the performances -- Different sample environments +The end station on the ID31 beamline is called the "micro-station": +- It is composed of several stacked stages, shown in Figure ref:fig:introduction_micro_station_dof: + - A translation stage (blue) + - Tilt stage (red) + - Spindle (yellow) for continuous rotation + - Micro hexapod (purple) + - The sample (cyan), which can weight up to 50kg + Typically the samples are fixed inside a sample environment, to provide special environment: high pressure, low or high temperatures, high magnetic field, etc. + +Presentation of the Micro-Station in details: +- Goal of each stage (e.g. micro-hexapod: static positioning, Ty and Rz: scans, ...) +- Stroke +- Initial design objectives: as stiff as possible, smallest errors as possible #+name: fig:introduction_micro_station -#+caption: The micro-station. CAD view is shown in (\subref{fig:introduction_micro_station_dof}) with the associated degrees of freedom. A picture of the micro-station is shown in (\subref{fig:introduction_micro_station_picture}) during the assembly process. +#+caption: CAD view of the ID31 Experimal Hutch (\subref{fig:introduction_id31_cad}). There are typically four main elements: the focusing optics in yellow, the sample stage in green, the sample itself in purple and the detector in blue. All these elements are fixed to the same granite. CAD view of the The micro-station with the associated degrees of freedom (\subref{fig:introduction_micro_station_dof}). #+attr_latex: :options [htbp] #+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_micro_station_dof} CAD view} -#+attr_latex: :options {0.49\textwidth} +#+attr_latex: :caption \subcaption{\label{fig:introduction_id31_cad} Experimental Hutch} +#+attr_latex: :options {0.52\textwidth} +#+begin_subfigure +#+attr_latex: :width 0.95\linewidth +[[file:figs/introduction_id31_station_detector.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_micro_station_dof} Micro-Station} +#+attr_latex: :options {0.44\textwidth} #+begin_subfigure #+attr_latex: :width 0.95\linewidth [[file:figs/introduction_micro_station_dof.png]] #+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_micro_station_picture} Picture} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.95\linewidth -[[file:figs/introduction_micro_station_picture.png]] -#+end_subfigure #+end_figure -**** Scientific experiments performed on ID31 +**** Example of Scientific experiments performed on ID31 -- Few words about science made on ID31 and why nano-meter accuracy is required -- Typical experiments (tomography, ...), various samples (up to 50kg), sample environments (high temp, cryo, etc..) - - Alignment of the sample, then - - Reflectivity - - Tomography - - Diffraction tomography: most critical -- Two example: - - Tomography: compute image as a function of the angle. To reconstruct 3D image, the position has to be known with good accuracy - [[cite:&schoeppler17_shapin_highl_regul_glass_archit]] - - Mapping: focused beam on the sample, 20nm step size, accuracy of the obtained image is directly linked to the beam size and the position accuracy/vibrations - [[cite:&sanchez-cano17_synch_x_ray_fluor_nanop]] +Such end station, being composed of several stacked stages, has an high mobility and allow for various scientific experiments (i.e. imaging techniques). -# From [[cite:&schropp20_ptynam;&schroer17_ptynam;&schroeck01_compen_desig_linear_time_invar]] -# For scanning microscopy and tomography it is essential to know where the beam hits the sample. -# Position uncertainties can arise from vibrations of the focusing optics and of the sample. -# The sample is scanned through the nanobeam, while the optics are kept fixed after initial alignment. +Two examples are here given to showcase the possibility offers by + + +Tomography experiment: +- Experimental setup illustrated in Figure ref:fig:introduction_tomography_schematic. +- A sample is place on the X-ray beam, and its vertical angle is controlled using a rotation stage. +- The detector images are captures for many different rotation angles. +- A 3D image of the sample, such as the one shown in Figure ref:fig:introduction_tomography_results (taken from [[cite:&schoeppler17_shapin_highl_regul_glass_archit]]), can then be reconstructed if the sample's point of interest stays on the beam while it is being rotated. + + +Mapping/Scanning experiments: +- Experimental setup illustrated in Figure ref:fig:introduction_scanning_schematic +- Optics are used to focus the X-ray beam on the sample. +- Then, the sample is moved perpendicularly to the beam (i.e. in the Y and Z directions) +- Example of obtained imagine in Figure ref:fig:introduction_scanning_results, the position of the sample is scanned with 20nm step increments [[cite:&sanchez-cano17_synch_x_ray_fluor_nanop]] +- The quality/accuracy of the obtained image is directly linked to the beam size and the positioning accuracy of the sample with respect to the focused X-ray beam. + Any vibrations and drifts would blur and deforms the obtained image. + + +Other imaging techniques used on ID31 include reflectivity, diffraction tomography, small and wide angle X-ray scattering. #+name: fig:introduction_tomography #+caption: Exemple of a tomography experiment. The sample is rotated and images are taken at several angles (\subref{fig:introduction_tomography_schematic}). Example of one 3D image obtained after tomography (\subref{fig:introduction_tomography_results}). @@ -1332,18 +1843,17 @@ Micro-Station: #+attr_latex: :caption \subcaption{\label{fig:introduction_tomography_schematic} Experimental setup} #+attr_latex: :options {0.65\textwidth} #+begin_subfigure -#+attr_latex: :width 0.95\linewidth +#+attr_latex: :scale 0.9 [[file:figs/introduction_tomography_schematic.png]] #+end_subfigure #+attr_latex: :caption \subcaption{\label{fig:introduction_tomography_results} Obtained image \cite{schoeppler17_shapin_highl_regul_glass_archit}} #+attr_latex: :options {0.34\textwidth} #+begin_subfigure -#+attr_latex: :width 0.95\linewidth +#+attr_latex: :height 4.5cm [[file:figs/introduction_tomography_picture.png]] #+end_subfigure #+end_figure - #+name: fig:introduction_scanning #+caption: Exemple of a scanning experiment. The sample is scanned in the Y-Z plane (\subref{fig:introduction_scanning_schematic}). Example of one 2D image obtained after scanning with a step size of 20nm (\subref{fig:introduction_scanning_results}). #+attr_latex: :options [htbp] @@ -1351,22 +1861,26 @@ Micro-Station: #+attr_latex: :caption \subcaption{\label{fig:introduction_scanning_schematic} Experimental setup} #+attr_latex: :options {0.65\textwidth} #+begin_subfigure -#+attr_latex: :width 0.95\linewidth +#+attr_latex: :scale 0.9 [[file:figs/introduction_scanning_schematic.png]] #+end_subfigure #+attr_latex: :caption \subcaption{\label{fig:introduction_scanning_results} Obtained image \cite{sanchez-cano17_synch_x_ray_fluor_nanop}} #+attr_latex: :options {0.34\textwidth} #+begin_subfigure -#+attr_latex: :width 0.95\linewidth +#+attr_latex: :height 4.5cm [[file:figs/introduction_scanning_picture.png]] #+end_subfigure #+end_figure ** Need of Accurate Positioning End-Stations with High Dynamics +:PROPERTIES: +:UNNUMBERED: t +:END: **** A push towards brighter and smaller beams -Improvement of both the light source and the instrumentation: -- EBS: smaller source + higher flux ref:fig:introduction_beam_3rd_4th_gen +Thanks to the improvement of both the light source and the instrumentation, smaller and more stable beams are available. + +First, the EBS upgrade allowed for a smaller source (especially in the horizontal direction) as illustrated in Figure ref:fig:introduction_beam_3rd_4th_gen. #+name: fig:introduction_beam_3rd_4th_gen #+caption: View of the ESRF X-ray beam before the EBS upgrade (\subref{fig:introduction_beam_3rd_gen}) and after the EBS upgrade (\subref{fig:introduction_beam_4th_gen}). The brilliance is increased, whereas the horizontal size and emittance are reduced. @@ -1386,45 +1900,34 @@ Improvement of both the light source and the instrumentation: #+end_subfigure #+end_figure -- ESRF Red Book (1987): very few beamline projects aiming even for 10 micron sized beams - Now optics exist for 10nm beams -- Better focusing optic (add some links): beam size in the order of 10 to 20nm FWHM (reference) ref:fig:introduction_moore_law_focus - crossed silicon compound refractive lenses, KB mirrors [17], zone plates [18], or multilayer Laue lenses [19] - [[cite:&barrett16_reflec_optic_hard_x_ray]] +- At the start of the ESRF, spot sizes for micro-focusing were in the order to $10\,\mu m$ [[cite:&riekel89_microf_works_at_esrf]]. +- Since then, lots of developments were perform to decrease the spot size, whether using Zone plates, Mirrors or Refractive lenses [[cite:&barrett16_reflec_optic_hard_x_ray]]. +- Each with their advantages and drawbacks. +- Such evolution is illustrated in Figure ref:fig:introduction_moore_law_focus +- Today, spot size in the order of 10 to 20nm FWHM are common for specialized nano-focusing beamline. #+name: fig:introduction_moore_law_focus -#+caption: Evolution of the measured spot size for different hard x-ray focusing elements. CRL, KB, FZP, MLL +#+caption: Evolution of the measured spot size for different hard x-ray focusing elements. CRL, KB, FZP, MLL. Adapated from\nbsp{}[[cite:&barrett24_x_optic_accel_based_light_sourc]] [[file:figs/introduction_moore_law_focus.png]] -Higher flux density (+high energy of the ID31 beamline) => Radiation damage: needs to scan the sample quite fast with respect to the focused beam +**** New Dynamical Positioning Needs -- Allowed by better detectors: higher sampling rates and lower noise => possible to scan fast - [[cite:&hatsui15_x_ray_imagin_detec_synch_xfel_sourc]] - -**** New dynamical positioning needs - -"from traditional step by step scans to /fly-scan/" - -Fast scans + needs of high accuracy and stability => need mechatronics system with: -- accurate metrology -- multi degree of freedom positioning systems -- fast feedback loops - -Shift from step by step scan to /fly-scan/ cite:huang15_fly_scan_ptych -- Much lower pixel size + large image => takes of lot of time if captured step by step. - Explain what is step by step scanning: move motors from point A to point B, stops, start detector acquisition, open shutter , close the shutter, move to point C, ... - -[[cite:&xu23_high_nsls_ii]] -#+begin_quote -In traditional step scan mode, each exposure position requires the system to stop prior to data acquisition, which may become a limiting factor when fast data collection is required. -Fly-scanning is chosen as a preferred solution that helps overcome such speed limitations [5, 6]. -In fly-scan mode, the sample keeps moving and a triggering system generates trigger signals based on the position of the sample or the time elapsed. -The trigger signals are used to control detector exposure. -#+end_quote +- Higher brilliance / flux density => "Radiation damage". +- This is especially true for high energy beamlines such as ID31. +- This means that the focused beam should not be kept on the sample for long period of time with the risk of damaging the sample. +Two solutions: +- Traditional way of performing experiments, illustrated in Figure ref:fig:introduction_scan_step. + The sample is positioned as wanted, the detector acquisition (i.e. "photon integration") starts, and then a beam shutter is opened for a short period of time to avoid radiation damage. + Then it goes to the next position, and this process is repeated. + This process can takes of lot of time when high resolution is wanted. +- An alternative is to perform what is called /fly-scan/ of /continuous-scan/, [[cite:&xu23_high_nsls_ii]]. + This is illustrated in Figure ref:fig:introduction_scan_fly. + As the sample undergoes continuous movement, the detector is triggered either based on the measured position of the sample of based on the time elapsed since the start of the motion. + This allows to perform experiments much faster [[cite:&huang15_fly_scan_ptych]] (i.e. better use of the beam time), and have potentially smaller pixel size. #+name: fig:introduction_scan_mode -#+caption: Two acquisition modes. In step-by-step mode (\subref{fig:introduction_scan_step}), the motor moves at the wanted imaged position, the detector acquisition is started, the shutter is openned briefly to have the wanted exposition, the detector acquisition is stopped, and the motor can move to a new position. In /fly-scan/ mode (\subref{fig:introduction_scan_fly}), the shutter is openned during all the motion, and the detector is acquired only at the wanted positions, on the /fly/. +#+caption: Two acquisition modes. In step-by-step mode (\subref{fig:introduction_scan_step}), the motor moves at the wanted imaged position, the detector acquisition is started, the shutter is openned briefly to have the wanted exposition, the detector acquisition is stopped, and the motor can move to a new position. In /fly-scan/ mode (\subref{fig:introduction_scan_fly}), the shutter is openned while the sample is in motion, and the detector is acquired only at the wanted positions, on the /fly/. #+attr_latex: :options [htbp] #+begin_figure #+attr_latex: :caption \subcaption{\label{fig:introduction_scan_step} Step by step scan} @@ -1441,25 +1944,80 @@ The trigger signals are used to control detector exposure. #+end_subfigure #+end_figure -Subject of this thesis: design of high performance positioning station with high dynamics and nanometer accuracy -** Nano Positioning End-Stations +Recent detector developments: +- Better spatial resolution, lower noise and higher frame rates [[cite:&hatsui15_x_ray_imagin_detec_synch_xfel_sourc]]. +- For typical scanning/tomography experiments: the detector integration time was in the order to 0.1s to 1s +- This long integration time (i.e. averaging) effectively "filters" out high frequency vibration in the beam position or of the sample's position, resulting in a apparent stable beam (but having bigger apparent size) +- With higher x-ray beam flux and lower noise in the detector, the integration time can be reduced. + Typical integration time can be in the over of 1ms, with frame rate in the order of 100Hz or more. + +This has two main implications related to positioning requirements: +- First: need for faster scans. For a same "pixel size", having an integration time reduced means that the scanning velocity is increased by the same amount. +- Second: the measurement is more sensitive to high frequency vibration. + This means that there is a need to control the position up to higher frequency, typically in the kHz range. + When performing dynamic error budgeting, the vibration needs to be integrated up to higher frequencies. + Not only the sample position need to be stable (i.e. free of drifts) with respect to the x-ray beam, it also need to be vibration-less + Combined with /fly-scan/ mode, this means that the position needs to be well controlled, even during scans. + +** Existing Nano Positioning End-Stations +:PROPERTIES: +:UNNUMBERED: t +:END: +**** Introduction :ignore: + +In order to highlight the specificity of the developed system: +- Options to tackle the need of higher accuracy and better dynamical characteristics of end-station is briefly discussed. +- The goal is to extract specific characteristics of the developed system that puts it apart from currently developed end-station. + **** End-Station with Stacked Stages -Stacked stages: -- errors are combined +Distinction between serial and parallel kinematics: Example of an end-station with 3DoF (Dx, Dy, Rz): Figure ref:fig:introduction_kinematics +- Stack stages (serial kinematics): Figure ref:fig:introduction_serial_kinematics + Each DoF is decoupled and positioned by only one actuator. + This usually lead to higher mobility. + But positioning errors / guiding errors of different stages are combined, and the overall positioning accuracy may be poor. + Similarly, the stiffness (i.e dynamical performances) of the overall end-station depends on the stiffness of the individual stages in all DoF, requiring extremely stiff stages. + When too many stages are stacked up, the overall stiffness is usually poor, and dynamical performances are not great. +- Parallel architecture: Figure ref:fig:introduction_parallel_kinematics + Motion induced by several actuator are combined to obtain the wanted DoF. + Theoretically, the controlled DoF are the same as the stacked stages architecture. + But in practice, motion are limited to very small strokes. + However, this has the advantage of having much higher stiffness, and therefore better dynamical performances. -To have acceptable performances / stability: -- limited number of stages -- high performances stages (air bearing etc...) +#+name: fig:introduction_kinematics +#+caption: Two positioning platforms with $D_x/D_y/R_z$ degrees of freedom. One is using serial kinematics (\subref{fig:introduction_serial_kinematics}), while the other uses parallel kinematics (\subref{fig:introduction_parallel_kinematics}) +#+attr_latex: :options [htbp] +#+begin_figure +#+attr_latex: :caption \subcaption{\label{fig:introduction_serial_kinematics} Serial Kinematics} +#+attr_latex: :options {0.49\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_serial_kinematics.png]] +#+end_subfigure +#+attr_latex: :caption \subcaption{\label{fig:introduction_parallel_kinematics} Parallel Kinematics} +#+attr_latex: :options {0.49\textwidth} +#+begin_subfigure +#+attr_latex: :scale 1 +[[file:figs/introduction_parallel_kinematics.png]] +#+end_subfigure +#+end_figure -Examples: -- ID01 [[cite:&leake19_nanod_beaml_id01]] -- ID11 [[cite:&wright20_new_oppor_at_mater_scien]] -- ID13 [[cite:&riekel10_progr_micro_nano_diffr_at]] +Most of end-station, because of the wanted high mobility, are composed of stacked stages. +In such case, their positioning performance solely depends on the accuracy of each of the individual stages. + +To have acceptable performance / stability: +- A limited number of high performances stages, such as air bearing spindles, are used [[cite:&riekel10_progr_micro_nano_diffr_at]] +- Extremely stable hutch temperature, while wanted stability usually reached only after several days without intervention in the hutch [[cite:&leake19_nanod_beaml_id01]] + +Two examples of such end-stations are shown in Figure ref:fig:introduction_passive_stations. +- ID16b [[cite:&martinez-criado16_id16b]]: uses a limited number of stacked stages, and uses extremely accurate air bearing spindle for tomography experiments +- ID11 [[cite:&wright20_new_oppor_at_mater_scien]]: Spindle, XYZ stage for scanning purposes and small hexapod used for pre-positioning + +But when many degrees of freedom are wanted, the overall accuracy and stability usually does not allow (or maybe is making working with nano-focused beam very difficult) for experiments with a nano-beam. #+name: fig:introduction_passive_stations -#+caption: Example of two nano end-stations without online metrology: (\subref{fig:introduction_endstation_id16b}) cite:&martinez-criado16_id16b and (\subref{fig:introduction_endstation_id11}) cite:wright20_new_oppor_at_mater_scien +#+caption: Example of two nano end-stations without online metrology: (\subref{fig:introduction_endstation_id16b}) [[cite:&martinez-criado16_id16b]] and (\subref{fig:introduction_endstation_id11}) [[cite:&wright20_new_oppor_at_mater_scien]] #+attr_latex: :options [htbp] #+begin_figure #+attr_latex: :caption \subcaption{\label{fig:introduction_endstation_id16b}ID16b} @@ -1476,25 +2034,33 @@ Examples: #+end_subfigure #+end_figure -Explain limitations => Thermal drifts, run-out errors of spindles (improved by using air bearing), straightness of translation stages, ... - **** Online Metrology The idea of having an external metrology to correct for errors is not new. -Several strategies: -- only used for measurements (post processing) -- for calibration -- for triggering detectors -- for real time positioning control (Figure ref:fig:introduction_active_stations) +Ideally, the relative position between the sample and the x-ray beam is measured. +In practice, it is not possible, but instead the position of the sample is measured with respect to the focusing optics and/or slits, providing an indirect measurement. -Sensors: +Several strategies: +- Used for know the relative position of the sample with respect to the x-ray beam. + Used during the post processing of the obtained data +- For calibration purposes. In that way repeatable errors can be compensated. +- For real time positioning control + For some applications, it is not only important to know the relative position of the sample with respect to the X-ray, but it is equality important to precisely control this position. + For instance, in order to keep a nano-particle on the beam while a tomography experiment is performed. + +Several Sensors have been used, but mainly two types: - Capacitive: [[cite:&schroer17_ptynam;&villar18_nanop_esrf_id16a_nano_imagin_beaml;&schropp20_ptynam]] -- Fiber Interferometers Interferometers: +- Fiber Interferometers Interferometers: more and more used - Attocube FPS3010 Fabry-Pérot interferometers: [[cite:&nazaretski15_pushin_limit;&stankevic17_inter_charac_rotat_stages_x_ray_nanot;&engblom18_nanop_resul;&nazaretski22_new_kirkp_baez_based_scann]] - Attocube IDS3010 Fabry-Pérot interferometers: [[cite:&holler17_omny_pin_versat_sampl_holder;&holler18_omny_tomog_nano_cryo_stage;&kelly22_delta_robot_long_travel_nano]] - PicoScale SmarAct Michelson interferometers: [[cite:&schroer17_ptynam;&schropp20_ptynam;&xu23_high_nsls_ii;&geraldes23_sapot_carnaub_sirius_lnls]] +Two examples are shown in Figure ref:fig:introduction_metrology_stations, in which metrology systems are used ot monitor the sample's position: +- Figure ref:fig:introduction_stages_wang: X8C beamline at National Synchrotron Light Source (NSLS). Capacitive sensors are used to calibrate the errors of the rotation stage, and are used during the alignment of different images captures during a tomography experiment [[cite:&wang12_autom_marker_full_field_hard]]. +- Figure ref:fig:introduction_stages_schroer: PtiNAMi microscope at P06 beamline at DESY. Three interferometers are pointed at a ball lens (1cm in diameter) located just below the sample. The spheres allows the sample to be rotated to perform tomography experiments. + Interferometers were reported to be used for monitoring, and is planned to be further used in a feedback loop with the piezoelectric stage located just below the sample [[cite:&schropp20_ptynam]]. + #+name: fig:introduction_metrology_stations #+caption: Two examples of end-station with integrated online metrology. (\subref{fig:introduction_stages_wang}) [[cite:&wang12_autom_marker_full_field_hard]] and (\subref{fig:introduction_stages_schroer}) [[cite:&schroer17_ptynam]] #+attr_latex: :options [htbp] @@ -1513,52 +2079,37 @@ Sensors: #+end_subfigure #+end_figure -#+name: tab:introduction_online_metrology -#+caption: End-Station integrating accurate online metrology systems. For all the examples, the sample used are in the micron scale. -#+attr_latex: :environment tabularx :width 1.0\linewidth :align cccccc -#+attr_latex: :center t :booktabs t :font \scriptsize -| *Architecture* | *Metrology* | *Usage* | *Institute* | *References* | -|-------------------------------------+-------------------+------------------+-------------+--------------------------------------------| -| Sample | 3 Capacitive | Post processing | NSLS | cite:&wang12_autom_marker_full_field_hard | -| XYZ Stage | $D_yD_zR_x$ | | (X8C) | Figure ref:fig:introduction_stages_wang | -| *Metrology Ring* | | | | | -| Spindle | | | | | -|-------------------------------------+-------------------+------------------+-------------+--------------------------------------------| -| *Ball-lens retroreflector* / Sample | 3 interferometers | Characterization | PETRA III | [[cite:&schroer17_ptynam;&schropp20_ptynam]] | -| XYZ piezo stage ($100\,\mu m$) | $D_yD_z$ | | (P06) | Figure ref:fig:introduction_stages_schroer | -| Spindle ($180\,\text{deg}$) | | | | | -|-------------------------------------+-------------------+------------------+-------------+--------------------------------------------| -| *Metrology Ring* / Sample | 2 interferometers | Detector | NSLS | [[cite:&xu23_high_nsls_ii]] | -| Spindle | $D_yD_z$ | triggering | (HRX) | | -| XYZ piezo stage | | | | | - **** Active Control of Positioning Errors -For some applications (especially when using a nano-beam), the position has not only to be measured, but to be controlled. -*Actuators*: +For some applications (especially when using a nano-beam), the sample's position has not only to be measured, but to be controlled using feedback loops. + +In that case, mainly three actuator types are used: - Piezoelectric: [[cite:&nazaretski15_pushin_limit;&holler17_omny_pin_versat_sampl_holder;&holler18_omny_tomog_nano_cryo_stage;&villar18_nanop_esrf_id16a_nano_imagin_beaml;&nazaretski22_new_kirkp_baez_based_scann]] - 3-phase linear motor: [[cite:&stankevic17_inter_charac_rotat_stages_x_ray_nanot;&engblom18_nanop_resul]] - Voice Coil: [[cite:&kelly22_delta_robot_long_travel_nano;&geraldes23_sapot_carnaub_sirius_lnls]] - -Bandwidth: rarely specificity. -Usually slow, so that only drifts are compensated. +In the literature, the feedback bandwidth for such end-station is rarely specificity. +It is usually slow (in the order of 1Hz), so that only (thermal) drifts are compensated. Only recently, high bandwidth (100Hz) have been reported with the use of voice coil actuators [[cite:&kelly22_delta_robot_long_travel_nano;&geraldes23_sapot_carnaub_sirius_lnls]]. -Full rotation for tomography: -- Spindle above XYZ stage: [[cite:&stankevic17_inter_charac_rotat_stages_x_ray_nanot;&holler17_omny_pin_versat_sampl_holder;&holler18_omny_tomog_nano_cryo_stage;&villar18_nanop_esrf_id16a_nano_imagin_beaml;&engblom18_nanop_resul;&nazaretski22_new_kirkp_baez_based_scann;&xu23_high_nsls_ii]] -- Spindle bellow XYZ stage: [[cite:&wang12_autom_marker_full_field_hard;&schroer17_ptynam;&schropp20_ptynam;&geraldes23_sapot_carnaub_sirius_lnls]] -Only for mapping: [[cite:&nazaretski15_pushin_limit;&kelly22_delta_robot_long_travel_nano]] +Two examples of end-station integrating online-metrology and feedback loops are shown in Figure ref:fig:introduction_active_stations: +- Figure ref:fig:introduction_stages_villar: ID16a beamline at ESRF (short stroke) Piezoelectric hexapod, rotation stage, Online metrology using many capacitive sensors. + The feedback loop (between the capacitive sensors and the piezoelectric hexapod) is used to compensate for errors of the rotation stage, and also to perform accurate scans with the hexapod. +- Figure ref:fig:introduction_stages_nazaretski: interferometers are used to measure the position of the sample. multi-layer Laue lenses (MLLs) are used to focus the beam down + Feedback control is used to compensate for drifts of the positioning stages. + +More extensive review of end-station with feedback loops based on online metrology will be given in section [...]. +# TODO - Add section to the review of stages with active vibration control ref:sec:nhexa_platform_review #+name: fig:introduction_active_stations #+caption: Example of two end-stations with real-time position feedback based on an online metrology. (\subref{fig:introduction_stages_villar}) [[cite:&villar18_nanop_esrf_id16a_nano_imagin_beaml]]. (\subref{fig:introduction_stages_nazaretski}) [[cite:&nazaretski17_desig_perfor_x_ray_scann;&nazaretski15_pushin_limit]] #+attr_latex: :options [htbp] #+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_stages_villar} ID16a} +#+attr_latex: :caption \subcaption{\label{fig:introduction_stages_villar} ID16a. =KB= is the focusing optics, =S= the sample, =C= the capacitive sensors and =LM= is the light microscope} #+attr_latex: :options {0.49\textwidth} #+begin_subfigure #+attr_latex: :width 0.95\linewidth -[[file:figs/introduction_stages_villar.png]] +[[file:figs/introduction_stages_villar.jpg]] #+end_subfigure #+attr_latex: :caption \subcaption{\label{fig:introduction_stages_nazaretski} 1 and 2 are stage to position the focusing optics. 3 is the sample location, 4 the sample stage and 5 the interferometers} #+attr_latex: :options {0.49\textwidth} @@ -1568,61 +2119,33 @@ Only for mapping: [[cite:&nazaretski15_pushin_limit;&kelly22_delta_robot_long_tr #+end_subfigure #+end_figure -Payload capabilities: +For tomography experiments, correcting for guiding errors of the rotation stage is of primary concern. +Two approaches can be used: +- Having the stage used for correcting the errors below the Spindle. [[cite:&stankevic17_inter_charac_rotat_stages_x_ray_nanot;&holler17_omny_pin_versat_sampl_holder;&holler18_omny_tomog_nano_cryo_stage;&villar18_nanop_esrf_id16a_nano_imagin_beaml;&engblom18_nanop_resul;&nazaretski22_new_kirkp_baez_based_scann;&xu23_high_nsls_ii]] +- Having the stage correcting the errors above the Spindle: [[cite:&wang12_autom_marker_full_field_hard;&schroer17_ptynam;&schropp20_ptynam;&geraldes23_sapot_carnaub_sirius_lnls]] + In all these cases, only XYZ stages are used to compensate for the guiding errors of the spindle. + +# Only for mapping: [[cite:&nazaretski15_pushin_limit;&kelly22_delta_robot_long_travel_nano]] + +In terms of payload capabilities: - All are only supported calibrated, micron scale samples - Higher sample masses to up to 500g have been reported in [[cite:&nazaretski22_new_kirkp_baez_based_scann;&kelly22_delta_robot_long_travel_nano]] 100 times heavier payload capabilities than previous stations with similar performances. -# #+attr_latex: :environment tabularx :width \linewidth :align lllll -# #+attr_latex: :center t :booktabs t :font \scriptsize - -#+name: tab:introduction_active_stations -#+caption: End-Stations with integrated feedback loops based on online metrology. Stages used for static positioning are ommited for readability. Stages used for feedback are indicated in bold font. -#+attr_latex: :environment tabularx :width 1.0\linewidth :align cccccc -#+attr_latex: :center t :booktabs t :font \scriptsize -| *Architecture* | *Metrology* | *Stroke* | *Bandwidth* | *Institute* | *References* | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Mirror / Sample | 3 Interferometers | | n/a | APS | [[cite:&nazaretski15_pushin_limit]] | -| *XYZ piezo motors* | $D_xD_yD_z$ | $D_xD_yD_z: 3\,\text{mm}$ | | | Figure ref:fig:introduction_stages_nazaretski | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Metrology Ring / Sample | 12 Capacitive | light | 10 Hz | ESRF | [[cite:&villar18_nanop_esrf_id16a_nano_imagin_beaml]] | -| Spindle | $D_xD_yD_zR_xR_y$ | $R_z: 180\,\text{deg}$ | | (ID16a) | Figure ref:fig:introduction_stages_villar | -| *Piezo Hexapod* | | $D_xD_yD_z: 50\,\mu m$ | | | | -| | | $R_x R_y: 500\,\mu \text{rad}$ | | | | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Spherical Reference / Sample | 5 Interferometers | light | n/a | PSI | [[cite:&holler17_omny_pin_versat_sampl_holder;&holler18_omny_tomog_nano_cryo_stage]] | -| Spindle | $D_yD_zR_x$ | $R_z: 365\,\text{deg}$ | | (OMNY) | | -| *Piezo Tripod* | | $D_xD_yD_z: 400\,\mu m$ | | | | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Cylindrical Reference / Sample | 5 Interferometers | light | n/a | Soleil | [[cite:&stankevic17_inter_charac_rotat_stages_x_ray_nanot;&engblom18_nanop_resul]] | -| Spindle | $D_xD_yD_zR_xR_y$ | $R_z: 360\,\text{deg}$ | | | | -| *Stacked XYZ linear motors* | | $D_xD_yD_z: 400\,\mu m$ | | | | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Metrology Ring / Sample | 3 Interferometers | up to 500g | n/a | NSLS | [[cite:&nazaretski22_new_kirkp_baez_based_scann]] | -| Spindle | $D_xD_yD_z$ | $R_z: 360\,\text{deg}$ | | (SRX) | | -| *XYZ piezo* | | $D_xD_yD_z: 100\,\mu m$ | | | | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Mirrors / Sample | 3 Interferometers | up to 350g | 100 Hz | Diamond | [[cite:&kelly22_delta_robot_long_travel_nano]] | -| *Parallel XYZ voice coil* | $D_xD_yD_z$ | $D_xD_yD_z: 3\,\text{mm}$ | | (I14) | | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Retroreflectors / Samples | 3 Interferometers | light | 100 Hz | LNLS | [[cite:&geraldes23_sapot_carnaub_sirius_lnls]] | -| *Parallel XYZ voice coil* | $D_xD_yD_z$ | $D_yD_z: 3\,\text{mm}$ | | (Carnauba) | | -| Spindle | | $R_z: \pm 110\,\text{deg}$ | | | | -|--------------------------------+-------------------+--------------------------------+-------------+-------------+-------------------------------------------------------------------------------------------------------| -| Sample | 6 Interferometers | *up to 50kg* | | ESRF | [[cite:&dehaeze18_sampl_stabil_for_tomog_exper;&dehaeze21_mechat_approac_devel_nano_activ_stabil_system]] | -| *Hexapod* | $D_xD_yD_zR_xR_y$ | | | (ID31) | Figure ref:fig:introduction_nass_concept_schematic | -| Spindle | | $R_z : 360\,\text{deg}$ | | | | -| Ry | | $R_y : \pm 3\,\text{deg}$ | | | | -| Ty | | $D_y : \pm 5\,\text{mm}$ | | | | - **** Long Stroke - Short Stroke architecture -Speak about two stage control? -- Long stroke + short stroke -- Usually applied to 1dof, 3dof (show some examples: disk drive, wafer scanner) -- Any application in 6DoF? Maybe new! -- In the table, say which ones are long stroke / short stroke. Some new stages are just long stroke (voice coil) +As shown in the previous examples, end-stations integrating online-metrology for nano-positioning are typically limited to only few degrees of freedom with only short stroke capabilities (in the order of $100\,\mu m$). + +An other strategy, illustrated in Figure ref:fig:introduction_two_stage_schematic, is to use two stacked stages for a single DoF: +- A long stroke, with limited accuracy is combined with short stroke stage with good dynamical properties. + The short stroke stage is used to position the sample based on the metrology measurement, while the long stroke is performing large motion. + +Such strategy is typically limited to few degrees of freedom: +- 1DoF as shown in Figure ref:fig:introduction_two_stage_control_example +- 3DoF as shown in Figure ref:fig:introduction_two_stage_control_h_bridge + +With such strategy, it is possible to obtain an overall stage with long stroke capability and with good accuracy and dynamical properties (brought by the short stroke stage). #+name: fig:introduction_two_stage_schematic #+caption: Typical Long Stroke - Short Stroke architecture. The long stroke stage is ... @@ -1647,70 +2170,49 @@ Speak about two stage control? #+end_figure * Challenge definition -** Multi degrees of freedom, long stroke and highly accurate positioning end station -**** Performance limitation of "stacked-stages" end-stations +**** Introduction :ignore: -Typical positioning end station (Figure ref:fig:introduction_translation_stage): -- stacked stages -- Ball-screw, linear guides, rotary motor +Based on the positioning requirements brought by the 4th light sources, improved focusing optics and development in detector technology, there are several challenges that need to be addressed. -Explain the limitation of performances: + +Smallest beam-size foreseen to be used on ID31 is around 200nm x 100nm +- During the experiments, the goal is therefore to keep to point of interest of the sample on the beam +- Therefore, the peak to peak positioning errors should be below 200nm in Dy and 100nm in Dz +- RMS errors (/ by 6.6) gives 30nmRMS in Dy and 15nmRMS in Dz. +- Also the tilt angle Ry error should be below <1.7urad, 250nrad RMS + + +As high frame rate detectors can be used, the specified position errors of the sample should hold even when taking into account high frequency vibrations. + + +Combined with the specificity of ID31: +- Build on top of the existing micro-station +- High required mobility to be able to perform many different experiments +- Handle large payloads (up to 50kg) + + +The current micro-station, while being composed of high performance positioning stages, the positioning accuracy is still limited by several effects: - Backlash, play, thermal expansion, guiding imperfections, ... - Give some numbers: straightness of the Ty stage for instance, change of $0.1^oC$ with steel gives x nm of motion - Vibrations - Possibility to have linear/rotary encoders that correct the motion in the considered DoF, but does not change anything to the other 5DoF -#+name: fig:introduction_translation_stage -#+caption: A classical translation stage composed of: a rotary motor and possibly reduction gears (in blue), a mechanism to transform the rotary motion to a translation (here a lead screw in green), a guiding mechanism (here linear rails and bearings in red). The mobile platform (in yellow) can then translate with respect to the fixed base. -[[file:figs/introduction_translation_stage.png]] +Typically, the final position accuracy is around 10um and 10urad. -Flexure based positioning stations may give better positioning requirements, but are limited to short stroke. -Advantages: no backlash, etc... -But: limited to short stroke -Picture of schematic of one positioning station based on flexure +The goal of this project is therefore to increase the positioning accuracy of the micro-station to fully exploit the new beam and detectors. -Explain example of Figure ref:fig:introduction_flexure_stage. +**** The Nano Active Stabilization System Concept -#+name: fig:introduction_flexure_stage -#+caption: A simple flexure stage -[[file:figs/introduction_flexure_stage.png]] +In order to address the new positioning requirements, the concept of the Nano Active Stabilization System (further referred to as the "NASS") is proposed. -Combining, long stroke and accuracy in multi-DoF is challenging. +It is composed of mainly four elements (Figure ref:fig:introduction_nass_concept_schematic): +- The micro station (in yellow) +- A 5 degrees of freedom metrology system (in red) +- A 5 or 6 degrees of freedom stabilization platform (in blue) +- Control system and associated instrumentation (in purple) -**** Positioning accuracy of the ID31 Micro-Station - -Presentation of the Micro-Station in details ref:fig:introduction_micro_station: -- Goal of each stage (e.g. micro-hexapod: static positioning, Ty and Rz: scans, ...) -- Stroke -- Initial design objectives: as stiff as possible, smallest errors as possible - -Explain that this micro-station can only have ~10um / 10urad of accuracy due to physical limitation. - -**** New positioning requirements - -- To benefits from nano-focusing optics, new source, etc... new positioning requirements -- Positioning requirements on ID31: - - Maybe make a table with the requirements and the associated performances of the micro-station - - Make tables with the wanted motion, stroke, accuracy in different DoF, etc.. -- Sample masses - -The goal in this thesis is to increase the positioning accuracy of the micro-station to fulfil the initial positioning requirements. - -*Goal*: Improve accuracy of 6DoF long stroke position platform - -** The Nano Active Stabilization System -**** NASS Concept - -In order to address the new positioning requirements, the concept of... - -Briefly describe the NASS concept. -6DoF vibration control platform on top of a complex positioning platform that correct positioning errors based on an external metrology - -It is composed of mainly four elements: -- The micro station -- A 5 degrees of freedom metrology system -- A 5 or 6 degrees of freedom stabilization platform -- Control system and associated instrumentation +It therefore corresponds to a 5 DoF vibration control platform on top of a complex positioning platform that correct positioning errors based on an external metrology. +That way, the goal is to improve the positioning accuracy of the micro-station from ~10um to less than 100nm, while keeping the same mobility and payload capabilities. #+name: fig:introduction_nass_concept_schematic #+caption: The Nano Active Stabilization System concept @@ -1718,124 +2220,51 @@ It is composed of mainly four elements: **** Online Metrology system -The accuracy of the NASS will only depend on the accuracy of the metrology system. +As the position of the sample is actively controlled based on the measured position, the accuracy of the NASS depends on the accuracy of the metrology system. -Requirements: -- 5 DoF -- long stroke -- nano-meter accurate -- high bandwidth +Such metrology system should: +- Measure the sample's position along 5 DoF (only the rotation along the vertical axis is not measured) +- Ideally measure the position with respect to the focusing optics +- Long stroke, as the micro-station as high mobility, compatible with the spindle continuous rotation +- Have an accuracy compatible with the positioning requirements +- High bandwidth -Concept: -- Fiber interferometers -- Spherical reflector with flat bottom -- Tracking system (tip-tilt mechanism) to keep the beam perpendicular to the mirror surface: Spherical mirror with center at the point of interest => No Abbe errors +Initial Concept: +- A spherical reflector with flat bottom is fixed just under the sample +- The center of the sphere coincide with the focused point of the X-ray +- Fiber interferometers are pointed both on spherical surface and on the bottom flat surface. +- A tracking system (tip-tilt mechanism) is used to keep the beam perpendicular to the mirror surface: Spherical mirror with center at the point of interest => No Abbe errors -- XYZ positions from at least 3 interferometers pointing at the spherical surface -- Rx/Ry angles from at least 3 interferometers pointing at the bottom flat surface +In that case: +- XYZ positions can be measured from at least 3 interferometers pointing at the spherical surface +- Rx/Ry angles are measured from at least 3 interferometers pointing at the bottom flat surface + +Such metrology system is a complex mechatronics system on its own. +This metrology system is not further discussed in this thesis as it is still under active development. +In the following of this thesis, it is supposed that the metrology system is accurate, and high bandwidth. #+name: fig:introduction_nass_metrology #+caption: 2D representation of the NASS metrology system. [[file:figs/introduction_nass_metrology.png]] -Complex mechatronics system on its own. -This metrology system is not further discussed in this thesis as it is still under active development. -In the following of this thesis, it is supposed that the metrology system is accurate, etc.. - **** Active Stabilization Platform -- 5 DoF -- High dynamics -- Nano-meter capable (no backlash) -- Accept payloads up to 50kg +The Active stabilization platform, located in between the sample and the micro-station should: +- Be able to move the sample in 5 DoF (the vertical rotation is not controlled) +- Have good dynamical properties such that the sample's position can be controlled up to high frequency +- Be capable to control the position down to nanometers. + It should therefore be free of play, backlash. + Low level of vibration should be induced by the active parts of the platform (such as actuator noise). +- It should accept payloads up to 50kg. -**** MIMO robust control strategies +A good candidate for the active platform is the Stewart platform: +- Parallel architecture, capable of controlling the motion in 6DoF +- Very popular for positioning and vibration control applications +- Many different designs, in terms of geometry, actuators, sensors and control strategies + Figure ref:fig:introduction_stewart_platform_piezo + # TODO - Review of Stewart platform ref:sec:detail_kinematics_stewart_review -Explain the robustness need? -- 24 7/7 ... -- That is why most of end-stations are based on well-proven design (stepper motors, linear guides, ball bearing, ...) -- Plant uncertainty: many different samples, use cases, rotating velocities, etc... - -Trade-off between robustness and performance in the design of feedback system. - -** Predictive Design - -- The performances of the system will depend on many factors: - - sensors - - actuators - - mechanical design - - achievable bandwidth -- Need to evaluate the different concepts, and predict the performances to guide the design -- The goal is to design, built and test this system such that it work as expected the first time. - Very costly system, so must be correct. -- Challenge: - - proper design methodology - - accurate models - -** Control Challenge - -High bandwidth, 6 DoF system for vibration control, fixed on top of a complex multi DoF positioning station, robust, ... - -- Many different configurations (tomography, Ty scans, slow fast, ...) -- Complex MIMO system. Dynamics of the system could be coupled to the complex dynamics of the micro station -- Rotation aspect, gyroscopic effects, actuators are rotating with respect to the sensors -- Robustness to payload change: very critical. - Say that high performance systems (lithography machines, etc...) works with calibrated payloads. - Being robust to change of payload inertia means large stability margins and therefore less performance. - -* [#A] Literature Review -*Maybe remove this section has it seems it is discussed elsewhere?* -** Multi-DoF dynamical positioning stations -**** Serial and Parallel Kinematics - -Example of several dynamical stations: -- XYZ piezo stages -- Delta robot? Octoglide? -- Stewart platform - -Serial vs parallel kinematics (table?) - -#+name: fig:introduction_kinematics -#+caption: Two positioning platforms with $D_x/D_y/R_z$ degrees of freedom. One is using serial kinematics (\subref{fig:introduction_serial_kinematics}), while the other uses parallel kinematics (\subref{fig:introduction_parallel_kinematics}) -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_serial_kinematics} Serial Kinematics} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_serial_kinematics.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_parallel_kinematics} Parallel Kinematics} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_parallel_kinematics.png]] -#+end_subfigure -#+end_figure - -**** Stewart platforms - -- [ ] Explain the normal stewart platform architecture -- [ ] Make a table that compares the different stewart platforms for vibration control. - Geometry (cubic), Actuator (soft, stiff), Sensor, Flexible joints, etc. - -#+name: fig:introduction_stewart_platform -#+caption: The Stewart Platform. Architecutre is shown in (\subref{fig:introduction_stewart_architecture}). Change of pose induce by change of strut length is shown in (\subref{fig:introduction_stewart_pose}) -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_stewart_architecture} Stewart Platform Architecture} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 0.8 -[[file:figs/introduction_stewart_architecture.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_stewart_pose} Change of mobile platform pose} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 0.8 -[[file:figs/introduction_stewart_pose.png]] -#+end_subfigure -#+end_figure +*Challenge*: Optimally designing such active platform #+name: fig:introduction_stewart_platform_piezo #+caption: Example of Stewart platforms. (\subref{fig:introduction_stewart_du14}) [[cite:&du14_piezo_actuat_high_precis_flexib]] and (\subref{fig:introduction_stewart_hauge04}) [[cite:&hauge04_sensor_contr_space_based_six]] @@ -1855,623 +2284,215 @@ Serial vs parallel kinematics (table?) #+end_subfigure #+end_figure -** Mechatronics approach -**** Predicting performances using models +**** MIMO robust control strategies -[[cite:&monkhorst04_dynam_error_budget]] -# high costs of the design process: the designed system must be *first time right*. -# When the system is finally build, its performance level should satisfy the specifications. -# No significant changes are allowed in the post design phase. -# Because of this, the designer wants to be able to predict the performance of the system a-priori and gain insight in the performance limiting factors of the system. +The NASS also includes feedback control: +- from the measured position of the sample using the online metrology +- from the wanted position of the sample (based on the wanted motion of each of the micro-station stages) +- the active platform is controlled in real time to stabilize the sample's position, compensating for all the errors of the micro-station stages, thermal drifts, etc. +When feedback control is being used, attention should be made on the stability of the feedback loop. +This is especially important in the context of a beamline application, as the instrument should be able to 24/7 with minimum intervention. +That is why most of end-stations are based on well-proven design (stepper motors, linear guides, ball bearing, ...). -Can use several models: -- Lumped mass-spring-damper models :: - usually uniaxial, easily put into equations, 1dof per considered mass - cite:rankers98_machin -- Multi-Body Models :: - usually 6dof per considered solid body, some may be constrained using joints -- Finite element models :: - Can include FEM into multi-body models: Sub structuring ([[cite:&brumund21_multib_simul_reduc_order_flexib_bodies_fea]]) +This need for robust feedback control is there made difficult due to: +- Many different configurations (tomography, Ty scans, slow fast, ...) +- Rotation aspect, gyroscopic effects, actuators are rotating with respect to the sensors +- The variety of payloads that will be used, with masses ranging from 1kg to 50kg. + Typically, high performance position feedback controllers are working with calibrated payloads (lithography machines, AFM, ...) + Being robust to change of payload inertia means larger stability margins and therefore less performance. +- For most of end-stations, the top stages (for small stroke scans) as well as the sample are quite light compared to the long stroke stages. + This way, the short stroke stage dynamics is not coupled to the dynamics of the stages bellow. + In the NASS case, the payload's mass may be one order of magnitude heavier than the mass of the long stroke top platform. + This induce a high coupling between the active platform and the micro-station. + This there may lead to a MIMO system with more complex dynamics and more coupling. +- This translates in change on the plant dynamics. + The feedback controller therefore need to be robust against plant uncertainty, while providing the wanted level of performance. -#+begin_src latex :file introduction_model_lumped.pdf :results file raw silent -\begin{tikzpicture} - % ==================== - % Parameters - % ==================== - \def\massw{2.2} % Width of the masses - \def\massh{0.8} % Height of the masses - \def\spaceh{1.2} % Height of the springs/dampers - \def\dispw{0.4} % Width of the dashed line for the displacement - \def\disph{0.4} % Height of the arrow for the displacements - \def\bracs{0.05} % Brace spacing vertically - \def\brach{-12pt} % Brace shift horizontaly - \def\fsensh{0.2} % Height of the force sensor - \def\velsize{0.2} % Size of the velocity sensor - % ==================== +**** Predictive Design / Mechatronics approach - - % ==================== - % Floor - % ==================== - \draw (-0.5*\massw, 0) -- (0.5*\massw, 0); - % \draw[dashed] (0.5*\massw, 0) -- ++(\dispw, 0); - % \draw[->, draw=colorred] (0.5*\massw+0.5*\dispw, 0) -- ++(0, \disph) node[right, color=colorred]{$x_{f}$}; - % ==================== - - % ==================== - % Granite - \begin{scope}[shift={(0, 0)}] - % Mass - \draw[fill=white] (-0.5*\massw, \spaceh) rectangle (0.5*\massw, \spaceh+\massh) node[pos=0.5]{$m_{1}$}; - - % Spring, Damper, and Actuator - \draw[spring] (-0.3*\massw, 0) -- (-0.3*\massw, \spaceh) node[midway, left=0.1]{$k_{1}$}; - \draw[damper] ( 0.3*\massw, 0) -- ( 0.3*\massw, \spaceh) node[midway, left=0.2]{$c_{1}$}; - - % Displacement - \draw[dashed] (0.5*\massw, \spaceh+\massh) -- ++(\dispw, 0); - \draw[->] (0.5*\massw+0.5*\dispw, \spaceh+\massh) -- ++(0, \disph) node[right]{$x_{1}$}; - \end{scope} - % ==================== - - - % ==================== - % Stages - \begin{scope}[shift={(0, \spaceh+\massh)}] - % Mass - \draw[fill=white] (-0.5*\massw, \spaceh) rectangle (0.5*\massw, \spaceh+\massh) node[pos=0.5]{$m_{2}$}; - - % Spring, Damper, and Actuator - \draw[spring] (-0.4*\massw, 0) -- (-0.4*\massw, \spaceh) node[midway, left=0.1]{$k_{1}$}; - \draw[damper] (0, 0) -- ( 0, \spaceh) node[midway, left=0.2]{$c_{2}$}; - \draw[actuator={0.45}{0.2}{black}] ( 0.4*\massw, 0) -- (0.4*\massw, \spaceh) node[midway, left=0.1]{$F$}; - - % Displacement - \draw[dashed] (0.5*\massw, \spaceh+\massh) -- ++(\dispw, 0); - \draw[->] (0.5*\massw+0.5*\dispw, \spaceh+\massh) -- ++(0, \disph) node[right]{$x_{2}$}; - \end{scope} - % ==================== -\end{tikzpicture} -#+end_src - -#+name: fig:introduction_models -#+caption: Types of models used when using a mechatronics approach. (\subref{fig:introduction_model_lumped}) (\subref{fig:introduction_model_multibody}) (\subref{fig:introduction_model_fem}) -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_model_lumped} Mass-Spring-Damper model} -#+attr_latex: :options {0.3\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_model_lumped.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_model_multibody} Multi-Body model} -#+attr_latex: :options {0.39\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.9\linewidth -[[file:figs/introduction_model_multibody.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_model_fem} Finite Element Model} -#+attr_latex: :options {0.3\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.9\linewidth -[[file:figs/introduction_model_fem.jpg]] -#+end_subfigure -#+end_figure - -**** Closed-Loop Simulations - -[[cite:&schmidt20_desig_high_perfor_mechat_third_revis_edition]] - -Once a model of the system is obtained: develop controller based on linearized model. - -#+begin_src latex :file introduction_closed_loop.pdf -\begin{tikzpicture} - \node[block] (controller) {Controller}; - \node[block, right = 1 of controller] (driver) {Driver}; - \node[block, right = 1 of driver] (actuator) {Actuator}; - \node[block, right = 1 of actuator, align=center] (system) {Mechanical\\System}; - \node[block, right = 1 of system] (sensor) {Sensor}; - - % Connections and labels - \draw[->] (controller.east) node[above right]{$u$} -- (driver.west); - \draw[->] (driver.east) -- (actuator.west); - \draw[->] (actuator.east) -- (system.west); - \draw[->] (system.east) --node[midway, above]{$y$} (sensor.west); - \draw[->] (sensor.east) -- ++(1.2, 0); - \draw[->] ($(sensor.east)+(0.6,0)$)node[branch]{}node[above]{$y_m$} -- ++(0, -2.0) -| (controller.south); - - \draw[<-] (controller.west) -- ++(-1.0, 0) node[above right]{$r$}; - \draw[<-] (driver.north) -- ++(0, 1.2) node[below right, align=left]{$d_u$}; - \draw[<-] (system.north) -- ++(0, 1.2) node[below right, align=left]{$d_y$}; - \draw[<-] (sensor.north) -- ++(0, 1.2) node[below right, align=left](sensornoise){$n$}; - - % Plant - \begin{scope}[on background layer] - \node[fit={(driver.south west) (sensornoise.north -| sensor.east)}, fill=black!20!white, draw, dashed, inner sep=8pt] (plant) {}; - \node[below] at (plant.north) {\textbf{Plant}}; - \end{scope} - - \draw[->, dashed] ($(plant.south) + (0, -0.3)$) arc (90:-90:0.3) -- ++(-2.5, 0) arc (-90:-270:0.3); - \node[left] at ($(plant.south) + (0, -0.6)$) {Feedback Loop} -\end{tikzpicture} -#+end_src - -#+RESULTS: -#+name: fig:introduction_closed_loop -#+caption: Block diagram of a typical feedback control architecture -[[file:figs/introduction_closed_loop.png]] - -Say what can limit the performances for a complex mechatronics systems as this one: -- Disturbances affecting the plant output $d_y$ -- Measurement noise $n$ -- DAC / amplifier noise (actuator) $d_u$ -- Feedback system / bandwidth -- $r$, $y_m$ - -Simulations can help evaluate the behavior of the system. - -**** Dynamic Error Budgeting - -[[cite:&monkhorst04_dynam_error_budget]] -# high costs of the design process: the designed system must be *first time right*. -# When the system is finally build, its performance level should satisfy the specifications. -# No significant changes are allowed in the post design phase. -# Because of this, the designer wants to be able to predict the performance of the system a-priori and gain insight in the performance limiting factors of the system. - -cite:jabben07_mechat - -[[cite:&okyay16_mechat_desig_dynam_contr_metrol]] -# *Classical error budgets*: -# Error budgets [23] are frequently used in the design of precision machines, in order to assess the contributions of different factors such as parasitic motions, thermal expansion, and servo accuracy, on the positioning accuracy of a machine. -# *Dynamic Error Budgeting*: -# Dynamic Error Budgeting (DEB) or ‘Spectral Analysis’ extends this concept to the realm of feedback control. -# Recognizing that the controller can provide only a finite attenuation of disturbance signals interfering with the servo, DEB provides a methodology for predicting the cumulative effect of such signals on the control error as a function of -# their spectral (frequency) content. -# The method can be used to predict the control accuracy of a system implemented using a set of certain devices under certain conditions before it is realized. -# Furthermore, as it is formulated in the frequency domain, it can be used to optimize the controller design as well, typically leading to an H2 - optimal control framework. -# In DEB, the disturbance signals are modeled with their power spectral density (PSD), assuming that they are stationary stochastic processes which are not correlated with each other. -# Then, these PSD’s are transmitted to the performance goal, most often the positioning error, using linear time invariant (LTI) system theory. -# The transmitted PSD’s are summed up into the variance of the performance goal, which constitutes a comparative measure of performance. -# Most importantly, the influence of different dynamic factors and disturbance sources, which have the greatest impact on the achievable performance (e.g., accuracy) can be easily spotted and improved, through this kind of analysis. -# *Applications*: -# An approach similar to DEB was followed to decompose the contribution of different noise sources on the hard disk position error in [1], [2], [45]. -# DEB has been used to assess the performance of a geophone and a vibration isolation system in [75]. -# Jabben[49] has used DEB in the mechatronic design of a magnetically suspended rotating platform. -# Aguirre et al. [3] have analyzed the performance of active aerostatic thrust bearings using DEB. - -- "the disturbance signals are modeled with their power spectral density (PSD), assuming that they are stationary stochastic processes which are not correlated with each other" -- Effects of $d_u$, $d_y$ and $n$ on $y$ can be estimated from their PSD and the closed-loop transfer functions - This gives a first idea of the limiting factor as a function of frequency. - In order to determine whether each disturbance/noise impact the performances, cumulative power spectrum can be used: this gives the RMS value - Then, this help to know the different actions to improve the performances: reduce sensor noise or driver electrical noise, work on reducing disturbances like damping resonances, increase feedback bandwidth, ...) - -#+name: fig:introduction_deb -#+caption: Tools used for the dynamic error budgeting. First the Power Spectral Density can be compared (\subref{fig:introduction_psd}). The cumulative power spectrum is shown in (\subref{fig:introduction_cps}). To compare the effectivness of different strategies, the cumulative power spectrum can be compared (\subref{fig:introduction_cps_cl}) -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_psd} Power Spectral Density - Open Loop} -#+attr_latex: :options {0.33\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.9\linewidth -[[file:figs/introduction_psd.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_cps} Cumulative Power Spectrum - Open Loop} -#+attr_latex: :options {0.33\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.9\linewidth -[[file:figs/introduction_cps.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_cps_cl} Cumulative Power Spectrum - Comparison} -#+attr_latex: :options {0.33\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.9\linewidth -[[file:figs/introduction_cps_cl.png]] -#+end_subfigure -#+end_figure - -** Stewart platforms: Control architecture -**** Introduction :ignore: - -Different control goals: -- Vibration Isolation ref:fig:introduction_stewart_isolation -- Position ref:fig:introduction_stewart_positioning - -Depending on the goal, different sensors and different architectures. - -For the NASS, both objectives. - -#+name: fig:introduction_stewart_control_goal -#+caption: Example of two control goals. In (\subref{fig:introduction_stewart_isolation}), the Stewart platform is used to isolate the payload from a vibration environment. In (\subref{fig:introduction_stewart_positioning}), the Stewart platform is used to position the payload along a defined trajectory. -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_stewart_isolation} Vibration Isolation} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_stewart_isolation.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_stewart_positioning} Positioning} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_stewart_positioning.png]] -#+end_subfigure -#+end_figure - - -**** Active Damping and Vibration Control - -Two main active vibration isolation strategies [[cite:&collette11_review_activ_vibrat_isolat_strat]]: -- IFF using collocated force sensors / load cell [[cite:&chesne16_enhan_dampin_flexib_struc_using_force_feedb]] -- Skyhook damping using inertial sensors (accelerometers, geophones), usually in the frame of the struts - -Usually, "decentralized", in the frame of the struts (Figure ref:fig:introduction_control_decentralized). -Optimization based on one "strut", and then applied to all the struts simultaneously to obtained a 6-DoF active damping / vibration control system. - -If narrow band disturbances: Adaptive feedforward control. - - -#+name: fig:introduction_damping -#+caption: Uniaxial vibration isolation strategies. Integral force feedback (\subref{fig:introduction_damping_iff}) and "sky-hook" damping (\subref{fig:introduction_damping_skyhook}). -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_damping_iff} Integral Force Feedback} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_damping_iff.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_damping_skyhook} "Sky-hook" Damping} -#+attr_latex: :options {0.49\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_damping_skyhook.png]] -#+end_subfigure -#+end_figure - - -#+name: fig:introduction_control_decentralized -#+caption: Decentralized control. Example of decentralized force feedback (\subref{fig:introduction_control_decentralized_schematic}), only three struts are shown for simplicity. Equivalent block diagram (\subref{fig:introduction_control_decentralized_diagram}), the controller is then diagonal. -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_control_decentralized_schematic} Decentralized Control applied on Stewart platform} -#+attr_latex: :options {0.54\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.95\linewidth -[[file:figs/introduction_control_decentralized_schematic.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_control_decentralized_diagram} Equivalent block diagram} -#+attr_latex: :options {0.45\textwidth} -#+begin_subfigure -#+attr_latex: :width 0.95\linewidth -[[file:figs/introduction_control_decentralized_diagram.png]] -#+end_subfigure -#+end_figure - -**** Position and Pointing Control - -Control based on position sensors. -Wanted position is generally expressed in the cartesian frame. - -Sensors can be: -- In the frame of the struts (LVDT, Encoder, Strain gauges): usually decentralized control (Figure ref:fig:introduction_control_decentralized_diagram) -- External sensors: centralized - -When using external sensors, a decoupling strategy is usually employed (Figure ref:fig:introduction_control_decoupling): -- Jacobian matrices: frame of the struts or cartesian frame -- Modal control -- Singular Value Decomposition -- Multivariable control: LQG, H-Infinity (Figure ref:fig:introduction_control_mimo) - -From [[cite:&thayer02_six_axis_vibrat_isolat_system]]: -#+begin_quote -Experimental closed-loop control results using the hexapod have shown that controllers designed using a decentralized single-strut design work well when compared to full multivariable methodologies. -#+end_quote - - -#+name: fig:introduction_control_mimo_vs_decoupling -#+caption: Two strategies to control a multi-inputs-multi-outputs system. Use of a multivariable controller (\subref{fig:introduction_control_mimo}), or first decouple the plant with matrices, and then designing several single-input-single-output controllers (\subref{fig:introduction_control_decoupling}) -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_control_mimo} Multivariable Control} -#+attr_latex: :options {0.33\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_control_mimo.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_control_decoupling} Decoupling Control} -#+attr_latex: :options {0.66\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_control_decoupling.png]] -#+end_subfigure -#+end_figure - -- Explain the Jacobian matrix - -When decoupling using the Jacobian matrix, the control can be performed in the frame of the struts (Figure ref:fig:introduction_control_centralized_struts) or in the cartesian frame (Figure ref:fig:introduction_control_centralized_cartesian). - -#+name: fig:introduction_control_centralized -#+caption: Two centralized control strategies. Express the position error in the frame of the struts and design one controller for each strut (\subref{fig:introduction_control_centralized_struts}). Design one controller for each direction, and then map the forces and torques to each struts (\subref{fig:introduction_control_centralized_cartesian}). -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_control_centralized_struts} Control in the frame of the struts} -#+attr_latex: :options {0.95\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_control_centralized_struts.png]] -#+end_subfigure - -\bigskip -#+attr_latex: :caption \subcaption{\label{fig:introduction_control_centralized_cartesian} Control in the cartesian frame} -#+attr_latex: :options {0.95\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_control_centralized_cartesian.png]] -#+end_subfigure -#+end_figure - -**** Use of Multiple Sensors - -Often, both vibration control and position control is wanted. -In that case, the use of multiple sensors can lead to improved performances. - -Sensors: -- collocated force (load cell) sensors -- collocated accelerometer -- displacement (eddy current) - -Several strategies can be employed: -- HAC-LAC cite:geng95_intel_contr_system_multip_degree,wang16_inves_activ_vibrat_isolat_stewar,li01_simul_vibrat_isolat_point_contr,pu11_six_degree_of_freed_activ,xie17_model_contr_hybrid_passiv_activ -- Sensor Fusion cite:tjepkema12_activ_ph,tjepkema12_sensor_fusion_activ_vibrat_isolat_precis_equip,hauge04_sensor_contr_space_based_six -- Two Sensor control: cite:hauge04_sensor_contr_space_based_six,tjepkema12_activ_ph - -Comparison between "two sensor control" and "sensor fusion" is given in [[cite:&beijen14_two_sensor_contr_activ_vibrat]]. - -#+name: fig:introduction_control_multiple_sensors -#+caption: Different control strategies when using multiple sensors. High Authority Control / Low Authority Control (\subref{fig:introduction_architecture_hac_lac}). Sensor Fusion (\subref{fig:introduction_architecture_sensor_fusion}). Two-Sensor Control (\subref{fig:introduction_architecture_two_sensor_control}) -#+attr_latex: :options [htbp] -#+begin_figure -#+attr_latex: :caption \subcaption{\label{fig:introduction_architecture_hac_lac} HAC-LAC} -#+attr_latex: :options {0.48\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_architecture_hac_lac.png]] -#+end_subfigure -#+attr_latex: :caption \subcaption{\label{fig:introduction_architecture_two_sensor_control} Two Sensor Control} -#+attr_latex: :options {0.48\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_architecture_two_sensor_control.png]] -#+end_subfigure - -\bigskip -#+attr_latex: :caption \subcaption{\label{fig:introduction_architecture_sensor_fusion} Sensor Fusion} -#+attr_latex: :options {0.95\textwidth} -#+begin_subfigure -#+attr_latex: :scale 1 -[[file:figs/introduction_architecture_sensor_fusion.png]] -#+end_subfigure -#+end_figure +- The performances of the system will depend on many factors: + - sensors + - actuators + - mechanical design + - achievable bandwidth +- Need to evaluate the different concepts, and predict the performances to guide the design +- The goal is to design, built and test this system such that it work as expected the first time. + Very costly system, so must be correct. +- *Challenge*: + - Proper design methodology + - Have accurate models to be able to compare different concepts + - Converge to a solution that gives the wanted level of performance * Original Contributions **** Introduction :ignore: -This thesis proposes several contributions in the fields of Control, Mechatronics Design and Experimental validation. +# TODO - All the papers should be cited -**** Active Damping of rotating mechanical systems using Integral Force Feedback +In order to address the challenges associated with the development of the Nano Active Stabilization Systems, this thesis proposes several original contributions in the fields of Control, Mechatronics Design and Experimental validation. -[[cite:&dehaeze20_activ_dampin_rotat_platf_integ_force_feedb;&dehaeze21_activ_dampin_rotat_platf_using]] -#+begin_quote -This paper investigates the use of Integral Force Feedback (IFF) for the active damping of rotating mechanical systems. -Guaranteed stability, typical benefit of IFF, is lost as soon as the system is rotating due to gyroscopic effects. -To overcome this issue, two modifications of the classical IFF control scheme are proposed. -The first consists of slightly modifying the control law while the second consists of adding springs in parallel with the force sensors. -Conditions for stability and optimal parameters are derived. -The results reveal that, despite their different implementations, both modified IFF control scheme have almost identical damping authority on the suspension modes. -#+end_quote +**** 6DoF vibration control of a rotating platform -**** Design of complementary filters using $\mathcal{H}_\infty$ Synthesis and sensor fusion +Long stroke / short stroke architectures are usually limited to 1DoF or 2DoF. +It is here extended to 6DoF. -[[cite:&dehaeze19_compl_filter_shapin_using_synth]] -[[cite:&verma20_virtual_sensor_fusion_high_precis_contr]] -[[cite:&tsang22_optim_sensor_fusion_method_activ]] +The active platform will not only compensate for errors of the rotation stage, but also of all other stages. -- Several uses (link to some papers). -- For the NASS, they could be use to further improve the robustness of the system. +To the author's knowledge, the use of a continuously rotating stewart platform for vibration control has not been proved in the literature. -**** [#A] Multi-body simulations with reduced order flexible bodies obtained by FEA +**** Mechatronics design approach -[[cite:&brumund21_multib_simul_reduc_order_flexib_bodies_fea]] +For the design of the NASS, a rigorous mechatronics design approach was conducted. + +[[cite:&dehaeze18_sampl_stabil_for_tomog_exper;&dehaeze21_mechat_approac_devel_nano_activ_stabil_system]] + +While not new, this approach is here applied from start to finish: +- From first concepts using basic models, to concept validation using mode accurate models +- Detailed design phase: models were used to optimize each individual components +- Experimental phase: models were still found to have great use. + For instance to better understand the observed behavior, and also to optimize the implemented control strategy. + +The use of dynamical models were used all along the development. + +This document, being written chronologically: +- Make clear how each models can be useful during different parts of the project +- Clearly show how each design decision are based on facts / clear conclusions extracted from the models +- While the developed system is quite specific for the presented application, it shows the effectiveness of this design approach + +# TODO - Use passive voice +I hope this document can make a small contribution in the adoption of the mechatronics approach for the design of future end-station and synchrotron instrumentation. + +**** Multi-body simulations with reduced order flexible bodies obtained by FEA + +One of the key tool that were used Combined multi-body / FEA techniques and experimental validation on a Stewart platform containing amplified piezoelectric actuators Super-element of amplified piezoelectric actuator / combined multibody-FEA technique, experimental validation on an amplified piezoelectric actuator and further validated on a complete stewart platform -#+begin_quote -We considered sub-components in the multi-body model as /reduced order flexible bodies/ representing the component’s modal behaviour with reduced mass and stiffness matrices obtained from finite element analysis (FEA) models. -These matrices were created from FEA models via modal reduction techniques, more specifically the /component mode synthesis/ (CMS). -This makes this design approach a combined multibody-FEA technique. -We validated the technique with a test bench that confirmed the good modelling capabilities using reduced order flexible body models obtained from FEA for an amplified piezoelectric actuator (APA). -#+end_quote +While not new: +- Experimentally validated with both an amplified piezoelectric actuator as well as a flexible joint +- It proved to be a very useful tool for the design/optimisation of components that have to be integrated in a larger system +- Believed to be quite useful for the development of future mechatronics instrumentation -**** Robustness by design +Subject of one publication [[cite:&brumund21_multib_simul_reduc_order_flexib_bodies_fea]] +Further detailed in Section [...]. +# TODO - Section ref:sec:detail_fem -- Design of a Stewart platform and associated control architecture that is robust to large plant uncertainties due to large variety of payload and experimental conditions. -- Instead of relying on complex controller synthesis (such as $\mathcal{H}_\infty$ synthesis or $\mu\text{-synthesis}$) to guarantee the robustness and performance. -- The approach here is to choose an adequate architecture (mechanics, sensors, actuators) such that controllers are robust by nature. -- Example: collocated actuator/sensor pair => controller can easily be made robust -- This is done by using models and using HAC-LAC architecture +**** Control Robustness by design -**** [#A] Mechatronics design +One of the main challenge is to design a system that is robust for all the experimental conditions: +- various rotational velocities used +- payload used can weight up to 50kg -Conduct a rigorous mechatronics design approach for a nano active stabilization system -[[cite:&dehaeze18_sampl_stabil_for_tomog_exper;&dehaeze21_mechat_approac_devel_nano_activ_stabil_system]] +Instead of relying on complex controller synthesis (such as $\mathcal{H}_\infty$ synthesis or $\mu\text{-synthesis}$) to guarantee the robustness and performance, the approach was to: +- Choose an adequate architecture (mechanics, sensors, actuators) such that controllers are robust by nature +- An example is the use of collocated actuator/sensor pairs, such that controller stability can be guaranteed using passivity principles +- To make informed choices on the chosen architecture: + - different ways to combine sensors (HAC-LAC, sensors fusion, two sensor control) were evaluated + - different decoupling strategy were compared + Such discussion, presented in Section [...] ,were found to be lacking in the literature. + # TODO - Section ref:sec:detail_control -Approach from start to finish: -- From first concepts using basic models, to concept validation -- Detailed design phase -- Experimental phase +**** Active Damping of rotating mechanical systems using Integral Force Feedback -Complete design with clear choices based on models. -Such approach, while not new, is here applied -This can be used for the design of future end-stations. +During the conceptual design, it was found the guaranteed stability of the active damping technique called "Integral Force Feedback" (IFF), is lost for rotating platforms as is the case for the NASS. -#+begin_src latex :file nass_introduction_mechatronics_approach.pdf -% \graphicspath{ {/home/thomas/Cloud/thesis/papers/dehaeze21_mechatronics_approach_nass/tikz/figs-tikz} } +To overcome this issue, two modifications of the classical IFF control scheme are proposed. +The first consists of slightly modifying the control law while the second consists of adding springs in parallel with the force sensors. +Conditions for stability and optimal parameters are derived. -\begin{tikzpicture} - % Styles - \tikzset{myblock/.style= {draw, thin, color=white!70!black, fill=white, text width=3cm, align=center, minimum height=1.4cm}}; - \tikzset{mylabel/.style= {anchor=north, below, font=\bfseries\small, color=black, text width=3cm, align=center}}; - \tikzset{mymodel/.style= {anchor=south, above, font=\small, color=black, text width=3cm, align=center}}; - \tikzset{mystep/.style= {->, ultra thick}}; +[[cite:&dehaeze20_activ_dampin_rotat_platf_integ_force_feedb;&dehaeze21_activ_dampin_rotat_platf_using]] - % Blocks - \node[draw, fill=lightblue, align=center, label={[mylabel, text width=8.0cm] Dynamical Models}, minimum height = 4.5cm, text width = 8.0cm] (model) at (0, 0) {}; +# TODO - Section ref:sec:rotating - \node[myblock, fill=lightgreen, label={[mylabel] Disturbances}, left = 3 of model.west] (dist) {}; - \node[myblock, fill=lightgreen, label={[mylabel] Micro Station}, below = 2pt of dist] (mustation) {}; - \node[myblock, fill=lightgreen, label={[mylabel] Nano Hexapod}, above = 2pt of dist] (nanohexapod) {}; +**** Design of complementary filters using $\mathcal{H}_\infty$ Synthesis - \node[myblock, fill=lightyellow, label={[mylabel] Mech. Design}, above = 1 of model.north] (mechanical) {}; - \node[myblock, fill=lightyellow, label={[mylabel] Instrumentation}, left = 2pt of mechanical] (instrumentation) {}; - \node[myblock, fill=lightyellow, label={[mylabel] FEM}, right = 2pt of mechanical] (fem) {}; +One way to combine sensors is to use "sensor fusion". +In such case, complementary filters are used to filter and combine the sensors. - \node[myblock, fill=lightred, label={[mylabel] Test Benches}, right = 3 of model.east] (testbenches) {}; - \node[myblock, fill=lightred, label={[mylabel] Assembly}, above = 2pt of testbenches] (mounting) {}; - \node[myblock, fill=lightred, label={[mylabel] Implementation}, below = 2pt of testbenches] (implementation) {}; +A method for designing such filter is proposed [[cite:&dehaeze19_compl_filter_shapin_using_synth]], that allows to shape the complementary filters norm, which allows to guarantee the performance of the fusion. +This was latter applied for optimal sensor fusion in gravitational wave detectors [[cite:&tsang22_optim_sensor_fusion_method_activ]]. +The design strategy is discussed in Section [...]. +# TODO - Section ref:sec:detail_control_sensor - % Text - \node[anchor=south, above, text width=8cm, align=left] at (model.south) {Extensive use of models for:\begin{itemize}[noitemsep,topsep=5pt]\item Extraction of transfer functions \\ \item Choice of appropriate control architecture \\ \item Tuning of control laws \\ \item Closed loop simulations \\ \item Noise budgets / Evaluation of performances \\ \item Sensibility to parameters / disturbances\end{itemize}\centerline{Models are at the core the mecatronic approach!}}; - - \node[mymodel] at (mustation.south) {Multiple stages \\ Complex dynamics}; - \node[mymodel] at (dist.south) {Ground motion \\ Position errors}; - \node[mymodel] at (nanohexapod.south) {Different concepts \\ Sensors, Actuators}; - - \node[mymodel] at (instrumentation.south) {Sensors, Actuators \\ Electronics}; - \node[mymodel] at (mechanical.south) {Proper integration \\ Ease of assembly}; - \node[mymodel] at (fem.south) {Optimize key parts: \\ Joints, Plates, APA}; - - \node[mymodel] at (mounting.south) {Struts \\ Nano-Hexapod}; - \node[mymodel] at (testbenches.south) {Instrumentation \\ APA, Struts}; - \node[mymodel] at (implementation.south) {Control tests \\ Micro Station}; - - % Links - \draw[->] (dist.east) -- node[above, midway]{{\small Measurements}} node[below,midway]{{\small Spectral Analysis}} (dist.east-|model.west); - \draw[->] (mustation.east) -- node[above, midway]{{\small Measurements}} node[below, midway]{{\small CAD Model}} (mustation.east-|model.west); - - \draw[->] ($(nanohexapod.east-|model.west)-(0, 0.15)$) -- node[below, midway]{{\small Optimization}} ($(nanohexapod.east)-(0, 0.15)$); - \draw[<-] ($(nanohexapod.east-|model.west)+(0, 0.15)$) -- node[above, midway]{{\small Model}} ($(nanohexapod.east)+(0, 0.15)$); - - \draw[->] ($(fem.south|-model.north)+(0.15, 0)$) -- node[right, midway]{{\small Specif.}} ($(fem.south)+(0.15,0)$); - \draw[<-] ($(fem.south|-model.north)-(0.15, 0)$) -- node[left, midway,align=right]{{\small Super}\\{\small Element}} ($(fem.south)-(0.15,0)$); - - \draw[->] ($(mechanical.south|-model.north)+(0.15, 0)$) -- node[right, midway]{{\small Specif.}} ($(mechanical.south)+(0.15,0)$); - \draw[<-] ($(mechanical.south|-model.north)-(0.15, 0)$) -- node[left, midway,align=right]{{\small CAD}\\{\small model}} ($(mechanical.south)-(0.15,0)$); - - \draw[->] ($(instrumentation.south|-model.north)+(0.15, 0)$) -- node[right, midway]{{\small Specif.}} ($(instrumentation.south)+(0.15,0)$); - \draw[<-] ($(instrumentation.south|-model.north)-(0.15, 0)$) -- node[left, midway]{{\small Model}} ($(instrumentation.south)-(0.15,0)$); - - \draw[->] ($(mounting.west-|model.east)+(0, 0.15)$) -- node[above, midway]{{\small Requirements}} ($(mounting.west)+(0, 0.15)$); - \draw[<-] ($(mounting.west-|model.east)-(0, 0.15)$) -- node[below, midway]{{\small Model refinement}} ($(mounting.west)-(0, 0.15)$); - - \draw[->] ($(testbenches.west-|model.east)+(0, 0.15)$) -- node[above, midway]{{\small Control Laws}} ($(testbenches.west)+(0, 0.15)$); - \draw[<-] ($(testbenches.west-|model.east)-(0, 0.15)$) -- node[below, midway]{{\small Model refinement}} ($(testbenches.west)-(0, 0.15)$); - - \draw[->] ($(implementation.west-|model.east)+(0, 0.15)$) -- node[above, midway]{{\small Control Laws}} ($(implementation.west)+(0, 0.15)$); - \draw[<-] ($(implementation.west-|model.east)-(0, 0.15)$) -- node[below, midway]{{\small Model refinement}} ($(implementation.west)-(0, 0.15)$); - - % Main steps - \node[font=\bfseries, rotate=90, anchor=south, above] (conceptual_phase_node) at (dist.west) {1 - Conceptual Phase}; - \node[font=\bfseries, above] (detailed_phase_node) at (mechanical.north) {2 - Detail Design Phase}; - \node[font=\bfseries, rotate=-90, anchor=south, above] (implementation_phase_node) at (testbenches.east) {3 - Experimental Phase}; - \begin{scope}[on background layer] - \node[fit={(conceptual_phase_node.north|-nanohexapod.north) (mustation.south east)}, fill=lightgreen!50!white, draw, inner sep=2pt] (conceptual_phase) {}; - \node[fit={(detailed_phase_node.north-|instrumentation.west) (fem.south east)}, fill=lightyellow!50!white, draw, inner sep=2pt] (detailed_phase) {}; - \node[fit={(implementation_phase_node.north|-mounting.north) (implementation.south west)}, fill=lightred!50!white, draw, inner sep=2pt] (implementation_phase) {}; - % \node[above left] at (dob.south east) {DOB}; - \end{scope} - - % Between main steps - \draw[mystep, postaction={decorate,decoration={raise=1ex,text along path,text align=center,text={Concept Validation}}}] (conceptual_phase.north) to[out=90, in=180] (detailed_phase.west); - \draw[mystep, postaction={decorate,decoration={raise=1ex,text along path,text align=center,text={Procurement}}}] (detailed_phase.east) to[out=0, in=90] (implementation_phase.north); - - % % Inside Model - % \node[inner sep=1pt, outer sep=6pt, anchor=north west, draw, fill=white, thin] (multibodymodel) at ($(model.north west) - (0, 0.5)$) - % {\includegraphics[width=5.6cm]{simscape_nano_hexapod.png}}; - - % \node[inner sep=1pt, outer sep=6pt, anchor=south west, draw, fill=white, thin] (simscape) at (model.south west) - % {\includegraphics[width=5.6cm]{simscape_picture.jpg}}; - - % % Feedback Model - % \node[inner sep=3pt, outer sep=6pt, anchor=north east, draw, fill=white, thin] (simscape_sim) at ($(model.north east) - (0, 0.5)$) - % {\includegraphics[width=3.6cm]{simscape_simulations.pdf}}; - - % % FeedBack - % \node[inner sep=3pt, outer sep=6pt, anchor=south east, draw, fill=white, thin] (feedback) at (model.south east) - % {\includegraphics[width=3.6cm]{classical_feedback_small.pdf}}; -\end{tikzpicture} -#+end_src - -#+name: fig:introduction_nass_mechatronics_approach -#+caption: Overview of the mechatronic approach used for the Nano-Active-Stabilization-System -#+attr_latex: :width \linewidth -#+RESULTS: -[[file:figs/introduction_nass_mechatronics_approach.png]] - -**** 6DoF vibration control of a rotating platform - -Vibration control in 5DoF of a rotating stage -To the author's knowledge, the use of a continuously rotating stewart platform for vibration control has not been proved in the literature. +The use of such complementary filters for feedback control can also lead to interesting control architecture, as discussed in [[cite:&verma20_virtual_sensor_fusion_high_precis_contr]] and further developed in Section [...]. +# TODO - Section ref:sec:detail_control_cf **** Experimental validation of the Nano Active Stabilization System -Demonstration of the improvement of the the positioning accuracy of a complex multi DoF (the micro-station) by several orders of magnitude (Section ...) using ... +The positioning performances of the Nano Active Stabilization System is experimentally evaluated/demonstrated on the ID31 beamline. + +The positioning accuracy of the micro-station is effectively improved from the ~10um down to ~100nm while performing experiments. +Robustness to sample's mass, and different experimental conditions are also verified. + +This therefore lead to a very versatile end-station, with high payload capabilities and nano-meter accuracy, allowing for full exploitation of the x-ray beam and associated instrumentation. + +To the author's knowledge, this is the first time such active platform is used to improve the accuracy of a positioning stage in 5DoF. +# TODO - Section ref:sec:test_id31 * Thesis Outline - Mechatronics Design Approach **** Introduction :ignore: -#+name: fig:introduction_overview_chapters -#+caption: Overview of the sections -#+attr_latex: :width \linewidth -[[file:figs/introduction_overview_chapters.png]] - -This thesis -- has a structure that follows the mechatronics design approach - -Is structured in three chapters that corresponds to the three mains parts of the proposed mechatronics approach. +This thesis is organized: +- to follow the mechatronics development approach, i.e. it is chronologically written. +The three chapters corresponds to the three mains parts of the proposed mechatronics approach. A brief overview of these three chapters is given bellow. **** Conceptual design development -- Start with simple models for witch trade offs can be easily understood (uniaxial) +- Talk about dynamic error budgeting +- Talk about used model + +The goal of this first chapter is to find a concept: +- that will provide the wanted performances with high level of confidence +- As such system is costly, a mechatronics design approach is used [[cite:&monkhorst04_dynam_error_budget]] to be able to design the system "right the first time": + - When the system is finally build, its performance level should satisfy the specifications. + - No significant changes are allowed in the post design phase. + - Because of this, the designer wants to be able to predict the performance of the system a-priori and gain insight in the performance limiting factors of the system. + +To do so: +- Dynamical models are used, with included disturbances, feedback architecture, etc.. + These models can be used to perform simulations, evaluate performances +- General idea is to start with very simple models, that can easily be understood (mass-spring-damper uniaxial model) - Increase the model complexity if important physical phenomenon are to be modelled (cf the rotating model) - Only when better understanding of the physical effects in play, and only if required, go for higher model complexity (here multi-body model) -- The system concept and main characteristics should be extracted from the different models and validated with closed-loop simulations with the most accurate model -- Once the concept is validated, the chosen concept can be design in mode details + +To better understand the performance limitations, for different models, /dynamic error budgeting/ [[cite:&monkhorst04_dynam_error_budget;&okyay16_mechat_desig_dynam_contr_metrol]] are performed. +It consists of: +- Disturbance and noise signals are modeled by their spectral content, i.e. by their power spectral density (PSD) +- The effect of each error sources on the final error, while the feedback control is active, can be easily estimated +- Therefore, the effect that have the greatest impact on the achievable performance can be easily spotted and improved +- Different concepts can be compared +- This tool is therefore key in better understanding the main limitations, and guide the determination of the best concept, early in the project. + +This chapter concludes with accurate time domain simulations of a tomography experiment, validating the developed concept. **** Detailed design -- During this detailed design phase, models are refined from the obtained CAD and using FEM -- The models are used to assists the design and to optimize each element based on dynamical analysis and closed-loop simulations -- The requirements for all the associated instrumentation can be determined from a dynamical noise budgeting -- After converging to a detailed design that give acceptable performance based on the models, the different parts can be ordered and the experimental phase begins +- In the second chapter, the chosen concept can be design in more details. +- First, the architecture and geometry of the active platform is optimized. +- Then, key components of the active platform, such as the flexible joints and the actuators, are optimized using the combined multi-body / FEA design approach. +- This allowed to optimize the components using very accurate models (thanks to FEA), while still being able to integrate these components in the complete multi-body model of the NASS for time domain simulations. +- Different aspects of the control of the NASS, such as the optimal use of multiple sensors integrated in the active platform, the best adapted decoupling strategy and the design of the robust controller, are then discussed. +- The requirements for all the associated instrumentation (digital to analog converters, analog to digital converters, voltage amplifiers, relative motion sensors) are chosen based on dynamic error budgeting. + Using such approach, it was made sure that none of these instrumentation will limit the overall performance of the system. +- This chapter concludes with a presentation of the final design of the active platform. **** Experimental validation -- It is advised that the important characteristics of the different elements are evaluated individually - Systematic validation/refinement of models with experimental measurements -- The obtained characteristics can be used to refine the models -- Then, an accurate model of the system is obtained which can be used during experimental tests (for control synthesis for instance) +After converging to a detailed design that give acceptable performance based on the models, the different parts were ordered and the experimental phase began. +Instead of directly assembling the active platform and testing it on the ID31 micro-station, a systematic approach was followed to characterize individual components. +- Therefore, actuators and flexible joints were individual characterized. + This allowed to update the model of these components, and obtained a more accurate model of the active platform + Systematic validation/refinement of models with experimental measurements +- Actuators and flexible joints were combined to form the active "struts" of the active platform. + These struts are also characterized +- Once the active platform were assembled, its dynamical model were found to over a very good match with the measured dynamics. +- This chapter conclude with the experimental tests on the ID31 micro-station of the complete NASS. +- Various scientific experiments are performed, such as tomography, and with various payload masses, to access the performances of the final system. * Bibliography :ignore: #+latex: \printbibliography[heading=bibintoc,title={Bibliography}] -* Footnotes -[fn:4]Capacitive sensors from Fogale Sensors -[fn:3]Attocube FPS3010 Fabry-Pérot interferometers -[fn:2]Attocube IDS3010 Fabry-Pérot interferometers -[fn:1]PicoScale SmarAct Michelson interferometers diff --git a/nass-introduction.pdf b/nass-introduction.pdf index 82d5d5b..3c3a39c 100644 Binary files a/nass-introduction.pdf and b/nass-introduction.pdf differ diff --git a/nass-introduction.tex b/nass-introduction.tex index 595d076..52574e9 100644 --- a/nass-introduction.tex +++ b/nass-introduction.tex @@ -1,4 +1,4 @@ -% Created 2024-05-30 Thu 15:51 +% Created 2025-04-17 Thu 17:23 % Intended LaTeX compiler: pdflatex \documentclass[a4paper, 10pt, DIV=12, parskip=full, bibliography=totoc]{scrreprt} @@ -13,7 +13,7 @@ pdftitle={Nano Active Stabilization System - Introduction}, pdfkeywords={}, pdfsubject={}, - pdfcreator={Emacs 29.3 (Org mode 9.6)}, + pdfcreator={Emacs 30.1 (Org mode 9.7.26)}, pdflang={English}} \usepackage{biblatex} @@ -23,14 +23,20 @@ \tableofcontents \clearpage - \chapter{Context of this thesis} -\section{Synchrotron Radiation Facilities} -\paragraph{Accelerating electrons to produce intense X-ray} +\section*{Synchrotron Radiation Facilities} +\subsubsection*{Accelerating electrons to produce intense X-ray} \begin{itemize} -\item Explain what is a Synchrotron: light source -\item Say how many there are in the world (\textasciitilde{}50). The main ones are shown in Figure \ref{fig:introduction_synchrotrons}. +\item Explain what is a Synchrotron: +\begin{itemize} +\item A particle (electrons) accelerator light source +\item Electrons produce very bright light, called synchrotron light +\item This very intense light, in the X-ray regime, is then used to study matter. +\end{itemize} +\item There are around 70 Synchrotron light sources in the world +Some of the main ones are shown in Figure \ref{fig:introduction_synchrotrons}. +This shows how useful the produced light is for the scientific community. \end{itemize} \begin{figure}[htbp] @@ -39,17 +45,34 @@ \caption{\label{fig:introduction_synchrotrons}Major synchrotron radiation facilities in the world. 3rd generation Synchrotrons are shown in blue. Planned upgrades to 4th generation are shown in green, and 4th generation Synchrotrons in operation are shown in red.} \end{figure} +There are two main parts in the Synchrotron: \begin{itemize} -\item Electron part: LINAC, Booster, Storage Ring \ref{fig:introduction_esrf_schematic} -\item Synchrotron radiation: Insertion device / Bending magnet -\item Many beamlines (large diversity in terms of instrumentation and science) -\item Science that can be performed: -\begin{itemize} -\item structural biology, structure of materials, matter at extreme, \ldots{} +\item The accelerator where electrons are accelerated close to the speed of light +The generation of the synchrotron light is made by placing magnetic fields on the electron beam path. +These are called Insertion device or Bending magnet. +\item The beamlines where the intense X-ray beam is used to study matter \end{itemize} +\subsubsection*{The European Synchrotron Radiation Facility} + +European Synchrotron Radiation Facility (ESRF): +\begin{itemize} +\item Joint research facility situated in Grenoble, France +\item supported by 19 countries +\item Opened for user operation in 1994: World's first third generation synchrotron (i.e. integrating ) \end{itemize} -\paragraph{The European Synchrotron Radiation Facility} +Accelerator (Schematically shown in Figure \ref{fig:introduction_esrf_schematic}): +\begin{itemize} +\item The Linear accelerator: where the electrons are +\item Booster: electrons are accelerated closed to the speed of light +\item Storage Ring: where the electrons are stored. Circumference of 844m. +\end{itemize} + +Then, there are over 40 beamlines all around the storage ring: +\begin{itemize} +\item Large diversity in terms of instrumentation and science +\item Science that can be performed: structural biology, structure of materials, matter at extreme, \ldots{} +\end{itemize} \begin{figure}[htbp] \begin{subfigure}{0.49\textwidth} @@ -66,13 +89,16 @@ \end{subfigure} \caption{\label{fig:instroduction_esrf}Schematic (\subref{fig:introduction_esrf_schematic}) and picture (\subref{fig:introduction_esrf_picture}) of the European Synchrotron Radiation Facility} \end{figure} +\subsubsection*{3rd and 4th Generation Light Sources} -\paragraph{3rd and 4th generation Synchrotrons} - -Brilliance: figure of merit for synchrotron - +ESRF–EBS (Extremely Brilliant Source): \cite{raimondi21_commis_hybrid_multib_achrom_lattic} \begin{itemize} -\item 4th generation light sources \cite{raimondi21_commis_hybrid_multib_achrom_lattic} +\item In August 2020, after a 20-month shutdown, the ESRF is the first fourth-generation +\item It uses a new storage ring concept that allows increased brilliance and coherence of the X-ray beams +The brilliance (also called brightness) is figure of merit for Synchrotron. +It corresponds to \ldots{} +100x increase with the EBS +\item This new beam offers many new scientific opportunities, but also creates many engineering challenges. \end{itemize} \begin{figure}[htbp] @@ -80,21 +106,19 @@ Brilliance: figure of merit for synchrotron \includegraphics[scale=1]{figs/introduction_moore_law_brillance.png} \caption{\label{fig:introduction_moore_law_brillance}Evolution of the peak brilliance (expressed in \(\text{photons}/s/mm^2/mrad^2/0.1\%BW\)) of synchrotron radiation facilities. Note the vertical logarithmic scale.} \end{figure} +\section*{The ID31 ESRF Beamline} +\subsubsection*{Beamline Layout} -\section{The ID31 ESRF Beamline} -\paragraph{Beamline Layout} - +Beamline ``layout'' refers to the series of elements located in between the ``light source'' and the sample. \begin{itemize} -\item General layout: source (insertion device), optical hutches (OH1, OH2), experimental hutch (EH) -\item Beamline layout (OH Figure \ref{fig:introduction_id31_oh}, EH \ref{fig:introduction_id31_cad}) -All these optical instruments are used to ``shape'' the x-ray beam as wanted (monochromatic, wanted size, focused, etc\ldots{}) -\item ID31 and Micro Station (Figure \ref{fig:introduction_id31_cad}) -Check \url{https://www.esrf.fr/UsersAndScience/Experiments/StructMaterials/ID31} -\url{https://www.wayforlight.eu/beamline/23244} -\item X-ray beam + detectors + sample stage -\item Focusing optics -\item Optical schematic with: source, lens, sample and detector. -Explain that what is the most important is the relative position between the sample and the lens. +\item Each beamline start with a ``white'' beam, which is just generated by the insertion device (i.e. the ``source''). +This beam has very high power (typically above kW), and is typically not directly used on the sample. +\item Instead, the beam goes through a series of optical elements (absorbers, mirrors, slits, monochromators, etc.) to filter and ``shape'' the x-ray beam as wanted. +These elements are located in several Optical Hutches as shown in Figure Figure \ref{fig:introduction_id31_oh} +\item Then, there is the Experimental Hutch (Figure \ref{fig:introduction_id31_cad}). +For some experiments (that are especially of interest here), focusing optics are used. +The sample is located on the sample stage (also called ``end-station''), as is used to position the sample with respect to the x-ray. +Detectors are used to capture the image formed by the x-ray going through the sample \item Explain the XYZ frame for all the thesis (ESRF convention: X: x-ray, Z gravity up) \end{itemize} @@ -115,100 +139,109 @@ Explain that what is the most important is the relative position between the sam \end{subfigure} \caption{\label{fig:introduction_id31_oh}Schematic of the two ID31 optical hutches: OH1 (\subref{fig:introduction_id31_oh1}) and OH2 (\subref{fig:introduction_id31_oh2}). Distance from the source (the insertion device) is indicated in meters.} \end{figure} +\subsubsection*{Positioning End Station: The Micro-Station} -\begin{figure}[htbp] -\centering -\includegraphics[scale=1,width=0.8\linewidth]{figs/introduction_id31_station_detector.png} -\caption{\label{fig:introduction_id31_cad}CAD view of the ID31 Experimal Hutch (EH). There are typically four main elements: the focusing optics in yellow, the sample stage in green, the sample itself in purple and the detector in blue. All these elements are fixed to the same granite.} -\end{figure} - -\paragraph{Positioning End Station: The Micro-Station} - -Micro-Station: +The end station on the ID31 beamline is called the ``micro-station'': \begin{itemize} -\item DoF with strokes: Ty, Ry, Rz, Hexapod -\item Experiments: tomography, reflectivity, truncation rod, \ldots{} -Make a table to explain the different ``experiments'' -\item Explain how it is used (positioning, scans), what it does. But not about the performances -\item Different sample environments +\item It is composed of several stacked stages, shown in Figure \ref{fig:introduction_micro_station_dof}: +\begin{itemize} +\item A translation stage (blue) +\item Tilt stage (red) +\item Spindle (yellow) for continuous rotation +\item Micro hexapod (purple) +\item The sample (cyan), which can weight up to 50kg +Typically the samples are fixed inside a sample environment, to provide special environment: high pressure, low or high temperatures, high magnetic field, etc. +\end{itemize} +\end{itemize} + +Presentation of the Micro-Station in details: +\begin{itemize} +\item Goal of each stage (e.g. micro-hexapod: static positioning, Ty and Rz: scans, \ldots{}) +\item Stroke +\item Initial design objectives: as stiff as possible, smallest errors as possible \end{itemize} \begin{figure}[htbp] -\begin{subfigure}{0.49\textwidth} +\begin{subfigure}{0.52\textwidth} +\begin{center} +\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_id31_station_detector.png} +\end{center} +\subcaption{\label{fig:introduction_id31_cad} Experimental Hutch} +\end{subfigure} +\begin{subfigure}{0.44\textwidth} \begin{center} \includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_micro_station_dof.png} \end{center} -\subcaption{\label{fig:introduction_micro_station_dof} CAD view} +\subcaption{\label{fig:introduction_micro_station_dof} Micro-Station} \end{subfigure} -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_micro_station_picture.png} -\end{center} -\subcaption{\label{fig:introduction_micro_station_picture} Picture} -\end{subfigure} -\caption{\label{fig:introduction_micro_station}The micro-station. CAD view is shown in (\subref{fig:introduction_micro_station_dof}) with the associated degrees of freedom. A picture of the micro-station is shown in (\subref{fig:introduction_micro_station_picture}) during the assembly process.} +\caption{\label{fig:introduction_micro_station}CAD view of the ID31 Experimal Hutch (\subref{fig:introduction_id31_cad}). There are typically four main elements: the focusing optics in yellow, the sample stage in green, the sample itself in purple and the detector in blue. All these elements are fixed to the same granite. CAD view of the The micro-station with the associated degrees of freedom (\subref{fig:introduction_micro_station_dof}).} \end{figure} +\subsubsection*{Example of Scientific experiments performed on ID31} -\paragraph{Scientific experiments performed on ID31} +Such end station, being composed of several stacked stages, has an high mobility and allow for various scientific experiments (i.e. imaging techniques). +Two examples are here given to showcase the possibility offers by + + +Tomography experiment: \begin{itemize} -\item Few words about science made on ID31 and why nano-meter accuracy is required -\item Typical experiments (tomography, \ldots{}), various samples (up to 50kg), sample environments (high temp, cryo, etc..) +\item Experimental setup illustrated in Figure \ref{fig:introduction_tomography_schematic}. +\item A sample is place on the X-ray beam, and its vertical angle is controlled using a rotation stage. +\item The detector images are captures for many different rotation angles. +\item A 3D image of the sample, such as the one shown in Figure \ref{fig:introduction_tomography_results} (taken from \cite{schoeppler17_shapin_highl_regul_glass_archit}), can then be reconstructed if the sample's point of interest stays on the beam while it is being rotated. +\end{itemize} + + +Mapping/Scanning experiments: \begin{itemize} -\item Alignment of the sample, then -\item Reflectivity -\item Tomography -\item Diffraction tomography: most critical -\end{itemize} -\item Two example: -\begin{itemize} -\item Tomography: compute image as a function of the angle. To reconstruct 3D image, the position has to be known with good accuracy -\cite{schoeppler17_shapin_highl_regul_glass_archit} -\item Mapping: focused beam on the sample, 20nm step size, accuracy of the obtained image is directly linked to the beam size and the position accuracy/vibrations -\cite{sanchez-cano17_synch_x_ray_fluor_nanop} -\end{itemize} +\item Experimental setup illustrated in Figure \ref{fig:introduction_scanning_schematic} +\item Optics are used to focus the X-ray beam on the sample. +\item Then, the sample is moved perpendicularly to the beam (i.e. in the Y and Z directions) +\item Example of obtained imagine in Figure \ref{fig:introduction_scanning_results}, the position of the sample is scanned with 20nm step increments \cite{sanchez-cano17_synch_x_ray_fluor_nanop} +\item The quality/accuracy of the obtained image is directly linked to the beam size and the positioning accuracy of the sample with respect to the focused X-ray beam. +Any vibrations and drifts would blur and deforms the obtained image. \end{itemize} + +Other imaging techniques used on ID31 include reflectivity, diffraction tomography, small and wide angle X-ray scattering. + \begin{figure}[htbp] \begin{subfigure}{0.65\textwidth} \begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_tomography_schematic.png} +\includegraphics[scale=1,scale=0.9]{figs/introduction_tomography_schematic.png} \end{center} \subcaption{\label{fig:introduction_tomography_schematic} Experimental setup} \end{subfigure} \begin{subfigure}{0.34\textwidth} \begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_tomography_picture.png} +\includegraphics[scale=1,height=4.5cm]{figs/introduction_tomography_picture.png} \end{center} \subcaption{\label{fig:introduction_tomography_results} Obtained image \cite{schoeppler17_shapin_highl_regul_glass_archit}} \end{subfigure} \caption{\label{fig:introduction_tomography}Exemple of a tomography experiment. The sample is rotated and images are taken at several angles (\subref{fig:introduction_tomography_schematic}). Example of one 3D image obtained after tomography (\subref{fig:introduction_tomography_results}).} \end{figure} - \begin{figure}[htbp] \begin{subfigure}{0.65\textwidth} \begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_scanning_schematic.png} +\includegraphics[scale=1,scale=0.9]{figs/introduction_scanning_schematic.png} \end{center} \subcaption{\label{fig:introduction_scanning_schematic} Experimental setup} \end{subfigure} \begin{subfigure}{0.34\textwidth} \begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_scanning_picture.png} +\includegraphics[scale=1,height=4.5cm]{figs/introduction_scanning_picture.png} \end{center} \subcaption{\label{fig:introduction_scanning_results} Obtained image \cite{sanchez-cano17_synch_x_ray_fluor_nanop}} \end{subfigure} \caption{\label{fig:introduction_scanning}Exemple of a scanning experiment. The sample is scanned in the Y-Z plane (\subref{fig:introduction_scanning_schematic}). Example of one 2D image obtained after scanning with a step size of 20nm (\subref{fig:introduction_scanning_results}).} \end{figure} +\section*{Need of Accurate Positioning End-Stations with High Dynamics} +\subsubsection*{A push towards brighter and smaller beams} -\section{Need of Accurate Positioning End-Stations with High Dynamics} -\paragraph{A push towards brighter and smaller beams} +Thanks to the improvement of both the light source and the instrumentation, smaller and more stable beams are available. -Improvement of both the light source and the instrumentation: -\begin{itemize} -\item EBS: smaller source + higher flux \ref{fig:introduction_beam_3rd_4th_gen} -\end{itemize} +First, the EBS upgrade allowed for a smaller source (especially in the horizontal direction) as illustrated in Figure \ref{fig:introduction_beam_3rd_4th_gen}. \begin{figure}[htbp] \begin{subfigure}{0.69\textwidth} @@ -227,52 +260,38 @@ Improvement of both the light source and the instrumentation: \end{figure} \begin{itemize} -\item ESRF Red Book (1987): very few beamline projects aiming even for 10 micron sized beams -Now optics exist for 10nm beams -\item Better focusing optic (add some links): beam size in the order of 10 to 20nm FWHM (reference) \ref{fig:introduction_moore_law_focus} -crossed silicon compound refractive lenses, KB mirrors [17], zone plates [18], or multilayer Laue lenses [19] -\cite{barrett16_reflec_optic_hard_x_ray} +\item At the start of the ESRF, spot sizes for micro-focusing were in the order to \(10\,\mu m\) \cite{riekel89_microf_works_at_esrf}. +\item Since then, lots of developments were perform to decrease the spot size, whether using Zone plates, Mirrors or Refractive lenses \cite{barrett16_reflec_optic_hard_x_ray}. +\item Each with their advantages and drawbacks. +\item Such evolution is illustrated in Figure \ref{fig:introduction_moore_law_focus} +\item Today, spot size in the order of 10 to 20nm FWHM are common for specialized nano-focusing beamline. \end{itemize} \begin{figure}[htbp] \centering \includegraphics[scale=1]{figs/introduction_moore_law_focus.png} -\caption{\label{fig:introduction_moore_law_focus}Evolution of the measured spot size for different hard x-ray focusing elements. CRL, KB, FZP, MLL} +\caption{\label{fig:introduction_moore_law_focus}Evolution of the measured spot size for different hard x-ray focusing elements. CRL, KB, FZP, MLL. Adapated from~\cite{barrett24_x_optic_accel_based_light_sourc}} \end{figure} - -Higher flux density (+high energy of the ID31 beamline) => Radiation damage: needs to scan the sample quite fast with respect to the focused beam +\subsubsection*{New Dynamical Positioning Needs} \begin{itemize} -\item Allowed by better detectors: higher sampling rates and lower noise => possible to scan fast -\cite{hatsui15_x_ray_imagin_detec_synch_xfel_sourc} +\item Higher brilliance / flux density => ``Radiation damage''. +\item This is especially true for high energy beamlines such as ID31. +\item This means that the focused beam should not be kept on the sample for long period of time with the risk of damaging the sample. \end{itemize} -\paragraph{New dynamical positioning needs} - -``from traditional step by step scans to \emph{fly-scan}'' - -Fast scans + needs of high accuracy and stability => need mechatronics system with: +Two solutions: \begin{itemize} -\item accurate metrology -\item multi degree of freedom positioning systems -\item fast feedback loops +\item Traditional way of performing experiments, illustrated in Figure \ref{fig:introduction_scan_step}. +The sample is positioned as wanted, the detector acquisition (i.e. ``photon integration'') starts, and then a beam shutter is opened for a short period of time to avoid radiation damage. +Then it goes to the next position, and this process is repeated. +This process can takes of lot of time when high resolution is wanted. +\item An alternative is to perform what is called \emph{fly-scan} of \emph{continuous-scan}, \cite{xu23_high_nsls_ii}. +This is illustrated in Figure \ref{fig:introduction_scan_fly}. +As the sample undergoes continuous movement, the detector is triggered either based on the measured position of the sample of based on the time elapsed since the start of the motion. +This allows to perform experiments much faster \cite{huang15_fly_scan_ptych} (i.e. better use of the beam time), and have potentially smaller pixel size. \end{itemize} -Shift from step by step scan to \emph{fly-scan} \cite{huang15_fly_scan_ptych} -\begin{itemize} -\item Much lower pixel size + large image => takes of lot of time if captured step by step. -Explain what is step by step scanning: move motors from point A to point B, stops, start detector acquisition, open shutter , close the shutter, move to point C, \ldots{} -\end{itemize} - -\cite{xu23_high_nsls_ii} -\begin{quote} -In traditional step scan mode, each exposure position requires the system to stop prior to data acquisition, which may become a limiting factor when fast data collection is required. -Fly-scanning is chosen as a preferred solution that helps overcome such speed limitations [5, 6]. -In fly-scan mode, the sample keeps moving and a triggering system generates trigger signals based on the position of the sample or the time elapsed. -The trigger signals are used to control detector exposure. -\end{quote} - - \begin{figure}[htbp] \begin{subfigure}{0.55\textwidth} \begin{center} @@ -286,205 +305,83 @@ The trigger signals are used to control detector exposure. \end{center} \subcaption{\label{fig:introduction_scan_fly} Fly scan} \end{subfigure} -\caption{\label{fig:introduction_scan_mode}Two acquisition modes. In step-by-step mode (\subref{fig:introduction_scan_step}), the motor moves at the wanted imaged position, the detector acquisition is started, the shutter is openned briefly to have the wanted exposition, the detector acquisition is stopped, and the motor can move to a new position. In \emph{fly-scan} mode (\subref{fig:introduction_scan_fly}), the shutter is openned during all the motion, and the detector is acquired only at the wanted positions, on the \emph{fly}.} +\caption{\label{fig:introduction_scan_mode}Two acquisition modes. In step-by-step mode (\subref{fig:introduction_scan_step}), the motor moves at the wanted imaged position, the detector acquisition is started, the shutter is openned briefly to have the wanted exposition, the detector acquisition is stopped, and the motor can move to a new position. In \emph{fly-scan} mode (\subref{fig:introduction_scan_fly}), the shutter is openned while the sample is in motion, and the detector is acquired only at the wanted positions, on the \emph{fly}.} \end{figure} -Subject of this thesis: design of high performance positioning station with high dynamics and nanometer accuracy -\chapter{Challenge definition} -\section{Multi degrees of freedom, long stroke and highly accurate positioning end station} -\paragraph{Performance limitation of ``stacked-stages'' end-stations} - -Typical positioning end station (Figure \ref{fig:introduction_translation_stage}): +Recent detector developments: \begin{itemize} -\item stacked stages -\item Ball-screw, linear guides, rotary motor +\item Better spatial resolution, lower noise and higher frame rates \cite{hatsui15_x_ray_imagin_detec_synch_xfel_sourc}. +\item For typical scanning/tomography experiments: the detector integration time was in the order to 0.1s to 1s +\item This long integration time (i.e. averaging) effectively ``filters'' out high frequency vibration in the beam position or of the sample's position, resulting in a apparent stable beam (but having bigger apparent size) +\item With higher x-ray beam flux and lower noise in the detector, the integration time can be reduced. +Typical integration time can be in the over of 1ms, with frame rate in the order of 100Hz or more. \end{itemize} -Explain the limitation of performances: +This has two main implications related to positioning requirements: \begin{itemize} -\item Backlash, play, thermal expansion, guiding imperfections, \ldots{} -\item Give some numbers: straightness of the Ty stage for instance, change of \(0.1^oC\) with steel gives x nm of motion -\item Vibrations -\item Possibility to have linear/rotary encoders that correct the motion in the considered DoF, but does not change anything to the other 5DoF +\item First: need for faster scans. For a same ``pixel size'', having an integration time reduced means that the scanning velocity is increased by the same amount. +\item Second: the measurement is more sensitive to high frequency vibration. +This means that there is a need to control the position up to higher frequency, typically in the kHz range. +When performing dynamic error budgeting, the vibration needs to be integrated up to higher frequencies. +Not only the sample position need to be stable (i.e. free of drifts) with respect to the x-ray beam, it also need to be vibration-less +Combined with \emph{fly-scan} mode, this means that the position needs to be well controlled, even during scans. +\end{itemize} +\section*{Existing Nano Positioning End-Stations} +In order to highlight the specificity of the developed system: +\begin{itemize} +\item Options to tackle the need of higher accuracy and better dynamical characteristics of end-station is briefly discussed. +\item The goal is to extract specific characteristics of the developed system that puts it apart from currently developed end-station. +\end{itemize} +\subsubsection*{End-Station with Stacked Stages} + +Distinction between serial and parallel kinematics: Example of an end-station with 3DoF (Dx, Dy, Rz): Figure \ref{fig:introduction_kinematics} +\begin{itemize} +\item Stack stages (serial kinematics): Figure \ref{fig:introduction_serial_kinematics} +Each DoF is decoupled and positioned by only one actuator. +This usually lead to higher mobility. +But positioning errors / guiding errors of different stages are combined, and the overall positioning accuracy may be poor. +Similarly, the stiffness (i.e dynamical performances) of the overall end-station depends on the stiffness of the individual stages in all DoF, requiring extremely stiff stages. +When too many stages are stacked up, the overall stiffness is usually poor, and dynamical performances are not great. +\item Parallel architecture: Figure \ref{fig:introduction_parallel_kinematics} +Motion induced by several actuator are combined to obtain the wanted DoF. +Theoretically, the controlled DoF are the same as the stacked stages architecture. +But in practice, motion are limited to very small strokes. +However, this has the advantage of having much higher stiffness, and therefore better dynamical performances. \end{itemize} \begin{figure}[htbp] -\centering -\includegraphics[scale=1]{figs/introduction_translation_stage.png} -\caption{\label{fig:introduction_translation_stage}A classical translation stage composed of: a rotary motor and possibly reduction gears (in blue), a mechanism to transform the rotary motion to a translation (here a lead screw in green), a guiding mechanism (here linear rails and bearings in red). The mobile platform (in yellow) can then translate with respect to the fixed base.} +\begin{subfigure}{0.49\textwidth} +\begin{center} +\includegraphics[scale=1,scale=1]{figs/introduction_serial_kinematics.png} +\end{center} +\subcaption{\label{fig:introduction_serial_kinematics} Serial Kinematics} +\end{subfigure} +\begin{subfigure}{0.49\textwidth} +\begin{center} +\includegraphics[scale=1,scale=1]{figs/introduction_parallel_kinematics.png} +\end{center} +\subcaption{\label{fig:introduction_parallel_kinematics} Parallel Kinematics} +\end{subfigure} +\caption{\label{fig:introduction_kinematics}Two positioning platforms with \(D_x/D_y/R_z\) degrees of freedom. One is using serial kinematics (\subref{fig:introduction_serial_kinematics}), while the other uses parallel kinematics (\subref{fig:introduction_parallel_kinematics})} \end{figure} -Flexure based positioning stations may give better positioning requirements, but are limited to short stroke. -Advantages: no backlash, etc\ldots{} -But: limited to short stroke -Picture of schematic of one positioning station based on flexure +Most of end-station, because of the wanted high mobility, are composed of stacked stages. +In such case, their positioning performance solely depends on the accuracy of each of the individual stages. -Explain example of Figure \ref{fig:introduction_flexure_stage}. - -\begin{figure}[htbp] -\centering -\includegraphics[scale=1]{figs/introduction_flexure_stage.png} -\caption{\label{fig:introduction_flexure_stage}A simple flexure stage} -\end{figure} - -Combining, long stroke and accuracy in multi-DoF is challenging. - -\paragraph{Positioning accuracy of the ID31 Micro-Station} - -Presentation of the Micro-Station in details \ref{fig:introduction_micro_station}: +To have acceptable performance / stability: \begin{itemize} -\item Goal of each stage (e.g. micro-hexapod: static positioning, Ty and Rz: scans, \ldots{}) -\item Stroke -\item Initial design objectives: as stiff as possible, smallest errors as possible +\item A limited number of high performances stages, such as air bearing spindles, are used \cite{riekel10_progr_micro_nano_diffr_at} +\item Extremely stable hutch temperature, while wanted stability usually reached only after several days without intervention in the hutch \cite{leake19_nanod_beaml_id01} \end{itemize} -Explain that this micro-station can only have \textasciitilde{}10um / 10urad of accuracy due to physical limitation. - -\paragraph{New positioning requirements} - +Two examples of such end-stations are shown in Figure \ref{fig:introduction_passive_stations}. \begin{itemize} -\item To benefits from nano-focusing optics, new source, etc\ldots{} new positioning requirements -\item Positioning requirements on ID31: -\begin{itemize} -\item Maybe make a table with the requirements and the associated performances of the micro-station -\item Make tables with the wanted motion, stroke, accuracy in different DoF, etc.. -\end{itemize} -\item Sample masses +\item ID16b \cite{martinez-criado16_id16b}: uses a limited number of stacked stages, and uses extremely accurate air bearing spindle for tomography experiments +\item ID11 \cite{wright20_new_oppor_at_mater_scien}: Spindle, XYZ stage for scanning purposes and small hexapod used for pre-positioning \end{itemize} -The goal in this thesis is to increase the positioning accuracy of the micro-station to fulfil the initial positioning requirements. - -\textbf{Goal}: Improve accuracy of 6DoF long stroke position platform - -\section{The Nano Active Stabilization System} -\paragraph{NASS Concept} - -In order to address the new positioning requirements, the concept of\ldots{} - -Briefly describe the NASS concept. -6DoF vibration control platform on top of a complex positioning platform that correct positioning errors based on an external metrology - -It is composed of mainly four elements: -\begin{itemize} -\item The micro station -\item A 5 degrees of freedom metrology system -\item A 5 or 6 degrees of freedom stabilization platform -\item Control system and associated instrumentation -\end{itemize} - -\begin{figure}[htbp] -\centering -\includegraphics[scale=1]{figs/introduction_nass_concept_schematic.png} -\caption{\label{fig:introduction_nass_concept_schematic}The Nano Active Stabilization System concept} -\end{figure} - -\paragraph{Online Metrology system} - -The accuracy of the NASS will only depend on the accuracy of the metrology system. - -Requirements: -\begin{itemize} -\item 5 DoF -\item long stroke -\item nano-meter accurate -\item high bandwidth -\end{itemize} - -Concept: -\begin{itemize} -\item Fiber interferometers -\item Spherical reflector with flat bottom -\item Tracking system (tip-tilt mechanism) to keep the beam perpendicular to the mirror surface: Spherical mirror with center at the point of interest => No Abbe errors - -\item XYZ positions from at least 3 interferometers pointing at the spherical surface -\item Rx/Ry angles from at least 3 interferometers pointing at the bottom flat surface -\end{itemize} - -\begin{figure}[htbp] -\centering -\includegraphics[scale=1]{figs/introduction_nass_metrology.png} -\caption{\label{fig:introduction_nass_metrology}2D representation of the NASS metrology system.} -\end{figure} - -Complex mechatronics system on its own. -This metrology system is not further discussed in this thesis as it is still under active development. -In the following of this thesis, it is supposed that the metrology system is accurate, etc.. - -\paragraph{Active Stabilization Platform} - -\begin{itemize} -\item 5 DoF -\item High dynamics -\item Nano-meter capable (no backlash) -\item Accept payloads up to 50kg -\end{itemize} - -\paragraph{MIMO robust control strategies} - -Explain the robustness need? -\begin{itemize} -\item 24 7/7 \ldots{} -\item That is why most of end-stations are based on well-proven design (stepper motors, linear guides, ball bearing, \ldots{}) -\item Plant uncertainty: many different samples, use cases, rotating velocities, etc\ldots{} -\end{itemize} - -Trade-off between robustness and performance in the design of feedback system. - -\section{Predictive Design} - -\begin{itemize} -\item The performances of the system will depend on many factors: -\begin{itemize} -\item sensors -\item actuators -\item mechanical design -\item achievable bandwidth -\end{itemize} -\item Need to evaluate the different concepts, and predict the performances to guide the design -\item The goal is to design, built and test this system such that it work as expected the first time. -Very costly system, so must be correct. -\item Challenge: -\begin{itemize} -\item proper design methodology -\item accurate models -\end{itemize} -\end{itemize} - -\section{Control Challenge} - -High bandwidth, 6 DoF system for vibration control, fixed on top of a complex multi DoF positioning station, robust, \ldots{} - -\begin{itemize} -\item Many different configurations (tomography, Ty scans, slow fast, \ldots{}) -\item Complex MIMO system. Dynamics of the system could be coupled to the complex dynamics of the micro station -\item Rotation aspect, gyroscopic effects, actuators are rotating with respect to the sensors -\item Robustness to payload change: very critical. -Say that high performance systems (lithography machines, etc\ldots{}) works with calibrated payloads. -Being robust to change of payload inertia means large stability margins and therefore less performance. -\end{itemize} - -\chapter{Literature Review} -\section{Nano Positioning End-Stations} -\paragraph{End-Station with Stacked Stages} - -Stacked stages: -\begin{itemize} -\item errors are combined -\end{itemize} - -To have acceptable performances / stability: -\begin{itemize} -\item limited number of stages -\item high performances stages (air bearing etc\ldots{}) -\end{itemize} - -Examples: -\begin{itemize} -\item ID01 \cite{leake19_nanod_beaml_id01} -\item ID11 \cite{wright20_new_oppor_at_mater_scien} -\item ID13 \cite{riekel10_progr_micro_nano_diffr_at} -\end{itemize} +But when many degrees of freedom are wanted, the overall accuracy and stability usually does not allow (or maybe is making working with nano-focused beam very difficult) for experiments with a nano-beam. \begin{figure}[htbp] \begin{subfigure}{0.49\textwidth} @@ -501,25 +398,27 @@ Examples: \end{subfigure} \caption{\label{fig:introduction_passive_stations}Example of two nano end-stations without online metrology: (\subref{fig:introduction_endstation_id16b}) \cite{martinez-criado16_id16b} and (\subref{fig:introduction_endstation_id11}) \cite{wright20_new_oppor_at_mater_scien}} \end{figure} - -Explain limitations => Thermal drifts, run-out errors of spindles (improved by using air bearing), straightness of translation stages, \ldots{} - -\paragraph{Online Metrology} +\subsubsection*{Online Metrology} The idea of having an external metrology to correct for errors is not new. +Ideally, the relative position between the sample and the x-ray beam is measured. +In practice, it is not possible, but instead the position of the sample is measured with respect to the focusing optics and/or slits, providing an indirect measurement. + Several strategies: \begin{itemize} -\item only used for measurements (post processing) -\item for calibration -\item for triggering detectors -\item for real time positioning control (Figure \ref{fig:introduction_active_stations}) +\item Used for know the relative position of the sample with respect to the x-ray beam. +Used during the post processing of the obtained data +\item For calibration purposes. In that way repeatable errors can be compensated. +\item For real time positioning control +For some applications, it is not only important to know the relative position of the sample with respect to the X-ray, but it is equality important to precisely control this position. +For instance, in order to keep a nano-particle on the beam while a tomography experiment is performed. \end{itemize} -Sensors: +Several Sensors have been used, but mainly two types: \begin{itemize} \item Capacitive: \cite{schroer17_ptynam,villar18_nanop_esrf_id16a_nano_imagin_beaml,schropp20_ptynam} -\item Fiber Interferometers Interferometers: +\item Fiber Interferometers Interferometers: more and more used \begin{itemize} \item Attocube FPS3010 Fabry-Pérot interferometers: \cite{nazaretski15_pushin_limit,stankevic17_inter_charac_rotat_stages_x_ray_nanot,engblom18_nanop_resul,nazaretski22_new_kirkp_baez_based_scann} \item Attocube IDS3010 Fabry-Pérot interferometers: \cite{holler17_omny_pin_versat_sampl_holder,holler18_omny_tomog_nano_cryo_stage,kelly22_delta_robot_long_travel_nano} @@ -527,6 +426,13 @@ Sensors: \end{itemize} \end{itemize} +Two examples are shown in Figure \ref{fig:introduction_metrology_stations}, in which metrology systems are used ot monitor the sample's position: +\begin{itemize} +\item Figure \ref{fig:introduction_stages_wang}: X8C beamline at National Synchrotron Light Source (NSLS). Capacitive sensors are used to calibrate the errors of the rotation stage, and are used during the alignment of different images captures during a tomography experiment \cite{wang12_autom_marker_full_field_hard}. +\item Figure \ref{fig:introduction_stages_schroer}: PtiNAMi microscope at P06 beamline at DESY. Three interferometers are pointed at a ball lens (1cm in diameter) located just below the sample. The spheres allows the sample to be rotated to perform tomography experiments. +Interferometers were reported to be used for monitoring, and is planned to be further used in a feedback loop with the piezoelectric stage located just below the sample \cite{schropp20_ptynam}. +\end{itemize} + \begin{figure}[htbp] \begin{subfigure}{0.49\textwidth} \begin{center} @@ -542,59 +448,36 @@ Sensors: \end{subfigure} \caption{\label{fig:introduction_metrology_stations}Two examples of end-station with integrated online metrology. (\subref{fig:introduction_stages_wang}) \cite{wang12_autom_marker_full_field_hard} and (\subref{fig:introduction_stages_schroer}) \cite{schroer17_ptynam}} \end{figure} +\subsubsection*{Active Control of Positioning Errors} -\begin{table}[htbp] -\caption{\label{tab:introduction_online_metrology}End-Station integrating accurate online metrology systems} -\centering -\scriptsize -\begin{tabularx}{1.0\linewidth}{ccccccc} -\toprule -\textbf{Architecture} & \textbf{Metrology} & \textbf{Usage} & \textbf{Stroke} & \textbf{Institute} & \textbf{References}\\ -\midrule -Sample & 3 Capacitive & Post processing & micron scale & NSLS & \cite{wang12_autom_marker_full_field_hard}\\ -XYZ Stage & \(D_yD_zR_x\) & & & (X8C) & Figure \ref{fig:introduction_stages_wang}\\ -\textbf{Metrology Ring} & & & & & \\ -Spindle & & & & & \\ -\midrule -\textbf{Ball-lens retroreflector} / Sample & 3 interferometers & Characterization & micron scale & PETRA III & \cite{schroer17_ptynam,schropp20_ptynam}\\ -XYZ piezo stage & \(D_yD_z\) & & XYZ: 100um & (P06) & Figure \ref{fig:introduction_stages_schroer}\\ -Spindle & & & Rz: 180 deg & & \\ -\midrule -\textbf{Metrology Ring} / Sample & 2 interferometers & Detector & micron scale & NSLS & \cite{xu23_high_nsls_ii}\\ -Spindle & \(D_yD_z\) & triggering & & (HRX) & \\ -XYZ piezo stage & & & & & \\ -\bottomrule -\end{tabularx} -\end{table} +For some applications (especially when using a nano-beam), the sample's position has not only to be measured, but to be controlled using feedback loops. -\paragraph{Active Control of Positioning Errors} -For some applications (especially when using a nano-beam), the position has not only to be measured, but to be controlled. - -\textbf{Actuators}: +In that case, mainly three actuator types are used: \begin{itemize} \item Piezoelectric: \cite{nazaretski15_pushin_limit,holler17_omny_pin_versat_sampl_holder,holler18_omny_tomog_nano_cryo_stage,villar18_nanop_esrf_id16a_nano_imagin_beaml,nazaretski22_new_kirkp_baez_based_scann} \item 3-phase linear motor: \cite{stankevic17_inter_charac_rotat_stages_x_ray_nanot,engblom18_nanop_resul} \item Voice Coil: \cite{kelly22_delta_robot_long_travel_nano,geraldes23_sapot_carnaub_sirius_lnls} \end{itemize} - -Bandwidth: rarely specificity. -Usually slow, so that only drifts are compensated. +In the literature, the feedback bandwidth for such end-station is rarely specificity. +It is usually slow (in the order of 1Hz), so that only (thermal) drifts are compensated. Only recently, high bandwidth (100Hz) have been reported with the use of voice coil actuators \cite{kelly22_delta_robot_long_travel_nano,geraldes23_sapot_carnaub_sirius_lnls}. -Full rotation for tomography: +Two examples of end-station integrating online-metrology and feedback loops are shown in Figure \ref{fig:introduction_active_stations}: \begin{itemize} -\item Spindle above XYZ stage: \cite{stankevic17_inter_charac_rotat_stages_x_ray_nanot,holler17_omny_pin_versat_sampl_holder,holler18_omny_tomog_nano_cryo_stage,villar18_nanop_esrf_id16a_nano_imagin_beaml,engblom18_nanop_resul,nazaretski22_new_kirkp_baez_based_scann,xu23_high_nsls_ii} -\item Spindle bellow XYZ stage: \cite{wang12_autom_marker_full_field_hard,schroer17_ptynam,schropp20_ptynam,geraldes23_sapot_carnaub_sirius_lnls} +\item Figure \ref{fig:introduction_stages_villar}: ID16a beamline at ESRF (short stroke) Piezoelectric hexapod, rotation stage, Online metrology using many capacitive sensors. +The feedback loop (between the capacitive sensors and the piezoelectric hexapod) is used to compensate for errors of the rotation stage, and also to perform accurate scans with the hexapod. +\item Figure \ref{fig:introduction_stages_nazaretski}: interferometers are used to measure the position of the sample. multi-layer Laue lenses (MLLs) are used to focus the beam down +Feedback control is used to compensate for drifts of the positioning stages. \end{itemize} -Only for mapping: \cite{nazaretski15_pushin_limit,kelly22_delta_robot_long_travel_nano} +More extensive review of end-station with feedback loops based on online metrology will be given in section [\ldots{}]. \begin{figure}[htbp] \begin{subfigure}{0.49\textwidth} \begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_stages_villar.png} +\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_stages_villar.jpg} \end{center} -\subcaption{\label{fig:introduction_stages_villar} ID16a} +\subcaption{\label{fig:introduction_stages_villar} ID16a. =KB= is the focusing optics, =S= the sample, =C= the capacitive sensors and =LM= is the light microscope} \end{subfigure} \begin{subfigure}{0.49\textwidth} \begin{center} @@ -605,68 +488,39 @@ Only for mapping: \cite{nazaretski15_pushin_limit,kelly22_delta_robot_long_trave \caption{\label{fig:introduction_active_stations}Example of two end-stations with real-time position feedback based on an online metrology. (\subref{fig:introduction_stages_villar}) \cite{villar18_nanop_esrf_id16a_nano_imagin_beaml}. (\subref{fig:introduction_stages_nazaretski}) \cite{nazaretski17_desig_perfor_x_ray_scann,nazaretski15_pushin_limit}} \end{figure} -Payload capabilities: +For tomography experiments, correcting for guiding errors of the rotation stage is of primary concern. +Two approaches can be used: +\begin{itemize} +\item Having the stage used for correcting the errors below the Spindle. \cite{stankevic17_inter_charac_rotat_stages_x_ray_nanot,holler17_omny_pin_versat_sampl_holder,holler18_omny_tomog_nano_cryo_stage,villar18_nanop_esrf_id16a_nano_imagin_beaml,engblom18_nanop_resul,nazaretski22_new_kirkp_baez_based_scann,xu23_high_nsls_ii} +\item Having the stage correcting the errors above the Spindle: \cite{wang12_autom_marker_full_field_hard,schroer17_ptynam,schropp20_ptynam,geraldes23_sapot_carnaub_sirius_lnls} +In all these cases, only XYZ stages are used to compensate for the guiding errors of the spindle. +\end{itemize} + +In terms of payload capabilities: \begin{itemize} \item All are only supported calibrated, micron scale samples \item Higher sample masses to up to 500g have been reported in \cite{nazaretski22_new_kirkp_baez_based_scann,kelly22_delta_robot_long_travel_nano} \end{itemize} 100 times heavier payload capabilities than previous stations with similar performances. +\subsubsection*{Long Stroke - Short Stroke architecture} -\begin{table}[htbp] -\caption{\label{tab:introduction_active_stations}End-Stations with integrated feedback loops based on online metrology. Stages used for static positioning are ommited for readability. Stages used for feedback are indicated in bold font.} -\centering -\scriptsize -\begin{tabularx}{1.0\linewidth}{cccccc} -\toprule -\textbf{Architecture} & \textbf{Metrology} & \textbf{Stroke} & \textbf{Bandwidth} & \textbf{Institute} & \textbf{References}\\ -\midrule -Mirror / Sample & 3 Interferometers & & & APS & \cite{nazaretski15_pushin_limit}\\ -\textbf{XYZ piezo motors} & \(D_xD_yD_z\) & \(D_xD_yD_z: 3\,\text{mm}\) & & & Figure \ref{fig:introduction_stages_nazaretski}\\ -\midrule -Metrology Ring / Sample & 12 Capacitive & light & 10 Hz & ESRF & \cite{villar18_nanop_esrf_id16a_nano_imagin_beaml}\\ -Spindle & \(D_xD_yD_zR_xR_y\) & \(R_z: 180\,\text{deg}\) & & (ID16a) & Figure \ref{fig:introduction_stages_villar}\\ -\textbf{Piezo Hexapod} & & \(D_xD_yD_z: 50\,\mu m\) & & & \\ - & & \(R_x R_y: 500\,\mu \text{rad}\) & & & \\ -\midrule -Spherical Reference / Sample & 5 Interferometers & light & & PSI & \cite{holler17_omny_pin_versat_sampl_holder,holler18_omny_tomog_nano_cryo_stage}\\ -Spindle & \(D_yD_zR_x\) & \(R_z: 365\,\text{deg}\) & & (OMNY) & \\ -\textbf{Piezo Tripod} & & \(D_xD_yD_z: 400\,\mu m\) & & & \\ -\midrule -Cylindrical Reference / Sample & 5 Interferometers & light & & Soleil & \cite{stankevic17_inter_charac_rotat_stages_x_ray_nanot,engblom18_nanop_resul}\\ -Spindle & \(D_xD_yD_zR_xR_y\) & \(R_z: 360\,\text{deg}\) & & & \\ -\textbf{Stacked XYZ linear motors} & & \(D_xD_yD_z: 400\,\mu m\) & & & \\ -\midrule -Metrology Ring / Sample & 3 Interferometers & up to 500g & & NSLS & \cite{nazaretski22_new_kirkp_baez_based_scann}\\ -Spindle & \(D_xD_yD_z\) & \(R_z: 360\,\text{deg}\) & & (SRX) & \\ -\textbf{XYZ piezo} & & \(D_xD_yD_z: 100\,\mu m\) & & & \\ -\midrule -Mirrors / Sample & 3 Interferometers & up to 350g & 100 Hz & Diamond & \cite{kelly22_delta_robot_long_travel_nano}\\ -\textbf{Parallel XYZ voice coil} & \(D_xD_yD_z\) & \(D_xD_yD_z: 3\,\text{mm}\) & & (I14) & \\ -\midrule -Retroreflectors / Samples & 3 Interferometers & light & 100 Hz & LNLS & \cite{geraldes23_sapot_carnaub_sirius_lnls}\\ -\textbf{Parallel XYZ voice coil} & \(D_xD_yD_z\) & \(D_yD_z: 3\,\text{mm}\) & & (Carnauba) & \\ -Spindle & & \(R_z: \pm 110\,\text{deg}\) & & & \\ -\midrule -Sample & 6 Interferometers & \textbf{up to 50kg} & & ESRF & \cite{dehaeze18_sampl_stabil_for_tomog_exper,dehaeze21_mechat_approac_devel_nano_activ_stabil_system}\\ -\textbf{Hexapod} & \(D_xD_yD_zR_xR_y\) & & & (ID31) & Figure \ref{fig:introduction_nass_concept_schematic}\\ -Spindle & & \(R_z : 360\,\text{deg}\) & & & \\ -Ry & & \(R_y : \pm 3\,\text{deg}\) & & & \\ -Ty & & \(D_y : \pm 5\,\text{mm}\) & & & \\ -\bottomrule -\end{tabularx} -\end{table} +As shown in the previous examples, end-stations integrating online-metrology for nano-positioning are typically limited to only few degrees of freedom with only short stroke capabilities (in the order of \(100\,\mu m\)). -\paragraph{Long Stroke - Short Stroke architecture} - -Speak about two stage control? +An other strategy, illustrated in Figure \ref{fig:introduction_two_stage_schematic}, is to use two stacked stages for a single DoF: \begin{itemize} -\item Long stroke + short stroke -\item Usually applied to 1dof, 3dof (show some examples: disk drive, wafer scanner) -\item Any application in 6DoF? Maybe new! -\item In the table, say which ones are long stroke / short stroke. Some new stages are just long stroke (voice coil) +\item A long stroke, with limited accuracy is combined with short stroke stage with good dynamical properties. +The short stroke stage is used to position the sample based on the metrology measurement, while the long stroke is performing large motion. \end{itemize} +Such strategy is typically limited to few degrees of freedom: +\begin{itemize} +\item 1DoF as shown in Figure \ref{fig:introduction_two_stage_control_example} +\item 3DoF as shown in Figure \ref{fig:introduction_two_stage_control_h_bridge} +\end{itemize} + +With such strategy, it is possible to obtain an overall stage with long stroke capability and with good accuracy and dynamical properties (brought by the short stroke stage). + \begin{figure}[htbp] \centering \includegraphics[scale=1]{figs/introduction_two_stage_schematic.png} @@ -688,58 +542,118 @@ Speak about two stage control? \end{subfigure} \caption{\label{fig:introduction_two_stage_example}(\subref{fig:introduction_two_stage_control_example}) \cite{shinno11_newly_devel_long_range_posit}, (\subref{fig:introduction_two_stage_control_h_bridge}) \cite{schmidt20_desig_high_perfor_mechat_third_revis_edition}} \end{figure} +\chapter{Challenge definition} +Based on the positioning requirements brought by the 4th light sources, improved focusing optics and development in detector technology, there are several challenges that need to be addressed. -\section{Multi-DoF dynamical positioning stations} -\paragraph{Serial and Parallel Kinematics} -Example of several dynamical stations: +Smallest beam-size foreseen to be used on ID31 is around 200nm x 100nm \begin{itemize} -\item XYZ piezo stages -\item Delta robot? Octoglide? -\item Stewart platform +\item During the experiments, the goal is therefore to keep to point of interest of the sample on the beam +\item Therefore, the peak to peak positioning errors should be below 200nm in Dy and 100nm in Dz +\item RMS errors (/ by 6.6) gives 30nmRMS in Dy and 15nmRMS in Dz. +\item Also the tilt angle Ry error should be below <1.7urad, 250nrad RMS \end{itemize} -Serial vs parallel kinematics (table?) -\begin{figure}[htbp] -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_serial_kinematics.png} -\end{center} -\subcaption{\label{fig:introduction_serial_kinematics} Serial Kinematics} -\end{subfigure} -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_parallel_kinematics.png} -\end{center} -\subcaption{\label{fig:introduction_parallel_kinematics} Parallel Kinematics} -\end{subfigure} -\caption{\label{fig:introduction_kinematics}Two positioning platforms with \(D_x/D_y/R_z\) degrees of freedom. One is using serial kinematics (\subref{fig:introduction_serial_kinematics}), while the other uses parallel kinematics (\subref{fig:introduction_parallel_kinematics})} -\end{figure} +As high frame rate detectors can be used, the specified position errors of the sample should hold even when taking into account high frequency vibrations. -\paragraph{Stewart platforms} +Combined with the specificity of ID31: \begin{itemize} -\item[{$\square$}] Explain the normal stewart platform architecture -\item[{$\square$}] Make a table that compares the different stewart platforms for vibration control. -Geometry (cubic), Actuator (soft, stiff), Sensor, Flexible joints, etc. +\item Build on top of the existing micro-station +\item High required mobility to be able to perform many different experiments +\item Handle large payloads (up to 50kg) \end{itemize} + +The current micro-station, while being composed of high performance positioning stages, the positioning accuracy is still limited by several effects: +\begin{itemize} +\item Backlash, play, thermal expansion, guiding imperfections, \ldots{} +\item Give some numbers: straightness of the Ty stage for instance, change of \(0.1^oC\) with steel gives x nm of motion +\item Vibrations +\item Possibility to have linear/rotary encoders that correct the motion in the considered DoF, but does not change anything to the other 5DoF +\end{itemize} + +Typically, the final position accuracy is around 10um and 10urad. + +The goal of this project is therefore to increase the positioning accuracy of the micro-station to fully exploit the new beam and detectors. +\subsubsection{The Nano Active Stabilization System Concept} + +In order to address the new positioning requirements, the concept of the Nano Active Stabilization System (further referred to as the ``NASS'') is proposed. + +It is composed of mainly four elements (Figure \ref{fig:introduction_nass_concept_schematic}): +\begin{itemize} +\item The micro station (in yellow) +\item A 5 degrees of freedom metrology system (in red) +\item A 5 or 6 degrees of freedom stabilization platform (in blue) +\item Control system and associated instrumentation (in purple) +\end{itemize} + +It therefore corresponds to a 5 DoF vibration control platform on top of a complex positioning platform that correct positioning errors based on an external metrology. +That way, the goal is to improve the positioning accuracy of the micro-station from \textasciitilde{}10um to less than 100nm, while keeping the same mobility and payload capabilities. + \begin{figure}[htbp] -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=0.8]{figs/introduction_stewart_architecture.png} -\end{center} -\subcaption{\label{fig:introduction_stewart_architecture} Stewart Platform Architecture} -\end{subfigure} -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=0.8]{figs/introduction_stewart_pose.png} -\end{center} -\subcaption{\label{fig:introduction_stewart_pose} Change of mobile platform pose} -\end{subfigure} -\caption{\label{fig:introduction_stewart_platform}The Stewart Platform. Architecutre is shown in (\subref{fig:introduction_stewart_architecture}). Change of pose induce by change of strut length is shown in (\subref{fig:introduction_stewart_pose})} +\centering +\includegraphics[scale=1]{figs/introduction_nass_concept_schematic.png} +\caption{\label{fig:introduction_nass_concept_schematic}The Nano Active Stabilization System concept} \end{figure} +\subsubsection{Online Metrology system} + +As the position of the sample is actively controlled based on the measured position, the accuracy of the NASS depends on the accuracy of the metrology system. + +Such metrology system should: +\begin{itemize} +\item Measure the sample's position along 5 DoF (only the rotation along the vertical axis is not measured) +\item Ideally measure the position with respect to the focusing optics +\item Long stroke, as the micro-station as high mobility, compatible with the spindle continuous rotation +\item Have an accuracy compatible with the positioning requirements +\item High bandwidth +\end{itemize} + +Initial Concept: +\begin{itemize} +\item A spherical reflector with flat bottom is fixed just under the sample +\item The center of the sphere coincide with the focused point of the X-ray +\item Fiber interferometers are pointed both on spherical surface and on the bottom flat surface. +\item A tracking system (tip-tilt mechanism) is used to keep the beam perpendicular to the mirror surface: Spherical mirror with center at the point of interest => No Abbe errors +\end{itemize} + +In that case: +\begin{itemize} +\item XYZ positions can be measured from at least 3 interferometers pointing at the spherical surface +\item Rx/Ry angles are measured from at least 3 interferometers pointing at the bottom flat surface +\end{itemize} + +Such metrology system is a complex mechatronics system on its own. +This metrology system is not further discussed in this thesis as it is still under active development. +In the following of this thesis, it is supposed that the metrology system is accurate, and high bandwidth. + +\begin{figure}[htbp] +\centering +\includegraphics[scale=1]{figs/introduction_nass_metrology.png} +\caption{\label{fig:introduction_nass_metrology}2D representation of the NASS metrology system.} +\end{figure} +\subsubsection{Active Stabilization Platform} + +The Active stabilization platform, located in between the sample and the micro-station should: +\begin{itemize} +\item Be able to move the sample in 5 DoF (the vertical rotation is not controlled) +\item Have good dynamical properties such that the sample's position can be controlled up to high frequency +\item Be capable to control the position down to nanometers. +It should therefore be free of play, backlash. +Low level of vibration should be induced by the active parts of the platform (such as actuator noise). +\item It should accept payloads up to 50kg. +\end{itemize} + +A good candidate for the active platform is the Stewart platform: +\begin{itemize} +\item Parallel architecture, capable of controlling the motion in 6DoF +\item Very popular for positioning and vibration control applications +\item Many different designs, in terms of geometry, actuators, sensors and control strategies +Figure \ref{fig:introduction_stewart_platform_piezo} +\end{itemize} + +\textbf{Challenge}: Optimally designing such active platform \begin{figure}[htbp] \begin{subfigure}{0.49\textwidth} @@ -756,410 +670,223 @@ Geometry (cubic), Actuator (soft, stiff), Sensor, Flexible joints, etc. \end{subfigure} \caption{\label{fig:introduction_stewart_platform_piezo}Example of Stewart platforms. (\subref{fig:introduction_stewart_du14}) \cite{du14_piezo_actuat_high_precis_flexib} and (\subref{fig:introduction_stewart_hauge04}) \cite{hauge04_sensor_contr_space_based_six}} \end{figure} +\subsubsection{MIMO robust control strategies} -\section{Mechatronics approach} -\paragraph{Predicting performances using models} - -\cite{monkhorst04_dynam_error_budget} -Can use several models: -\begin{description} -\item[{Lumped mass-spring-damper models}] usually uniaxial, easily put into equations, 1dof per considered mass -\cite{rankers98_machin} -\item[{Multi-Body Models}] usually 6dof per considered solid body, some may be constrained using joints -\item[{Finite element models}] Can include FEM into multi-body models: Sub structuring (\cite{brumund21_multib_simul_reduc_order_flexib_bodies_fea}) -\end{description} - -\begin{figure}[htbp] -\begin{subfigure}{0.3\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_model_lumped.png} -\end{center} -\subcaption{\label{fig:introduction_model_lumped} Mass-Spring-Damper model} -\end{subfigure} -\begin{subfigure}{0.39\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.9\linewidth]{figs/introduction_model_multibody.png} -\end{center} -\subcaption{\label{fig:introduction_model_multibody} Multi-Body model} -\end{subfigure} -\begin{subfigure}{0.3\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.9\linewidth]{figs/introduction_model_fem.jpg} -\end{center} -\subcaption{\label{fig:introduction_model_fem} Finite Element Model} -\end{subfigure} -\caption{\label{fig:introduction_models}Types of models used when using a mechatronics approach. (\subref{fig:introduction_model_lumped}) (\subref{fig:introduction_model_multibody}) (\subref{fig:introduction_model_fem})} -\end{figure} - -\paragraph{Closed-Loop Simulations} - -\cite{schmidt20_desig_high_perfor_mechat_third_revis_edition} - -Once a model of the system is obtained: develop controller based on linearized model. - -\begin{figure}[htbp] -\centering -\includegraphics[scale=1]{figs/introduction_closed_loop.png} -\caption{\label{fig:introduction_closed_loop}Block diagram of a typical feedback control architecture} -\end{figure} - -Say what can limit the performances for a complex mechatronics systems as this one: +The NASS also includes feedback control: \begin{itemize} -\item Disturbances affecting the plant output \(d_y\) -\item Measurement noise \(n\) -\item DAC / amplifier noise (actuator) \(d_u\) -\item Feedback system / bandwidth -\item \(r\), \(y_m\) +\item from the measured position of the sample using the online metrology +\item from the wanted position of the sample (based on the wanted motion of each of the micro-station stages) +\item the active platform is controlled in real time to stabilize the sample's position, compensating for all the errors of the micro-station stages, thermal drifts, etc. \end{itemize} -Simulations can help evaluate the behavior of the system. +When feedback control is being used, attention should be made on the stability of the feedback loop. +This is especially important in the context of a beamline application, as the instrument should be able to 24/7 with minimum intervention. +That is why most of end-stations are based on well-proven design (stepper motors, linear guides, ball bearing, \ldots{}). -\paragraph{Dynamic Error Budgeting} - -\cite{monkhorst04_dynam_error_budget} -\cite{jabben07_mechat} - -\cite{okyay16_mechat_desig_dynam_contr_metrol} +This need for robust feedback control is there made difficult due to: \begin{itemize} -\item ``the disturbance signals are modeled with their power spectral density (PSD), assuming that they are stationary stochastic processes which are not correlated with each other'' -\item Effects of \(d_u\), \(d_y\) and \(n\) on \(y\) can be estimated from their PSD and the closed-loop transfer functions -This gives a first idea of the limiting factor as a function of frequency. -In order to determine whether each disturbance/noise impact the performances, cumulative power spectrum can be used: this gives the RMS value -Then, this help to know the different actions to improve the performances: reduce sensor noise or driver electrical noise, work on reducing disturbances like damping resonances, increase feedback bandwidth, \ldots{}) +\item Many different configurations (tomography, Ty scans, slow fast, \ldots{}) +\item Rotation aspect, gyroscopic effects, actuators are rotating with respect to the sensors +\item The variety of payloads that will be used, with masses ranging from 1kg to 50kg. +Typically, high performance position feedback controllers are working with calibrated payloads (lithography machines, AFM, \ldots{}) +Being robust to change of payload inertia means larger stability margins and therefore less performance. +\item For most of end-stations, the top stages (for small stroke scans) as well as the sample are quite light compared to the long stroke stages. +This way, the short stroke stage dynamics is not coupled to the dynamics of the stages bellow. +In the NASS case, the payload's mass may be one order of magnitude heavier than the mass of the long stroke top platform. +This induce a high coupling between the active platform and the micro-station. +This there may lead to a MIMO system with more complex dynamics and more coupling. +\item This translates in change on the plant dynamics. +The feedback controller therefore need to be robust against plant uncertainty, while providing the wanted level of performance. \end{itemize} - -\begin{figure}[htbp] -\begin{subfigure}{0.33\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.9\linewidth]{figs/introduction_psd.png} -\end{center} -\subcaption{\label{fig:introduction_psd} Power Spectral Density - Open Loop} -\end{subfigure} -\begin{subfigure}{0.33\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.9\linewidth]{figs/introduction_cps.png} -\end{center} -\subcaption{\label{fig:introduction_cps} Cumulative Power Spectrum - Open Loop} -\end{subfigure} -\begin{subfigure}{0.33\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.9\linewidth]{figs/introduction_cps_cl.png} -\end{center} -\subcaption{\label{fig:introduction_cps_cl} Cumulative Power Spectrum - Comparison} -\end{subfigure} -\caption{\label{fig:introduction_deb}Tools used for the dynamic error budgeting. First the Power Spectral Density can be compared (\subref{fig:introduction_psd}). The cumulative power spectrum is shown in (\subref{fig:introduction_cps}). To compare the effectivness of different strategies, the cumulative power spectrum can be compared (\subref{fig:introduction_cps_cl})} -\end{figure} - -\section{Stewart platforms: Control architecture} -Different control goals: -\begin{itemize} -\item Vibration Isolation \ref{fig:introduction_stewart_isolation} -\item Position \ref{fig:introduction_stewart_positioning} -\end{itemize} - -Depending on the goal, different sensors and different architectures. - -For the NASS, both objectives. - -\begin{figure}[htbp] -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_stewart_isolation.png} -\end{center} -\subcaption{\label{fig:introduction_stewart_isolation} Vibration Isolation} -\end{subfigure} -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_stewart_positioning.png} -\end{center} -\subcaption{\label{fig:introduction_stewart_positioning} Positioning} -\end{subfigure} -\caption{\label{fig:introduction_stewart_control_goal}Example of two control goals. In (\subref{fig:introduction_stewart_isolation}), the Stewart platform is used to isolate the payload from a vibration environment. In (\subref{fig:introduction_stewart_positioning}), the Stewart platform is used to position the payload along a defined trajectory.} -\end{figure} - - -\paragraph{Active Damping and Vibration Control} - -Two main active vibration isolation strategies \cite{collette11_review_activ_vibrat_isolat_strat}: -\begin{itemize} -\item IFF using collocated force sensors / load cell \cite{chesne16_enhan_dampin_flexib_struc_using_force_feedb} -\item Skyhook damping using inertial sensors (accelerometers, geophones), usually in the frame of the struts -\end{itemize} - -Usually, ``decentralized'', in the frame of the struts (Figure \ref{fig:introduction_control_decentralized}). -Optimization based on one ``strut'', and then applied to all the struts simultaneously to obtained a 6-DoF active damping / vibration control system. - -If narrow band disturbances: Adaptive feedforward control. - - -\begin{figure}[htbp] -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_damping_iff.png} -\end{center} -\subcaption{\label{fig:introduction_damping_iff} Integral Force Feedback} -\end{subfigure} -\begin{subfigure}{0.49\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_damping_skyhook.png} -\end{center} -\subcaption{\label{fig:introduction_damping_skyhook} "Sky-hook" Damping} -\end{subfigure} -\caption{\label{fig:introduction_damping}Uniaxial vibration isolation strategies. Integral force feedback (\subref{fig:introduction_damping_iff}) and ``sky-hook'' damping (\subref{fig:introduction_damping_skyhook}).} -\end{figure} - - -\begin{figure}[htbp] -\begin{subfigure}{0.54\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_control_decentralized_schematic.png} -\end{center} -\subcaption{\label{fig:introduction_control_decentralized_schematic} Decentralized Control applied on Stewart platform} -\end{subfigure} -\begin{subfigure}{0.45\textwidth} -\begin{center} -\includegraphics[scale=1,width=0.95\linewidth]{figs/introduction_control_decentralized_diagram.png} -\end{center} -\subcaption{\label{fig:introduction_control_decentralized_diagram} Equivalent block diagram} -\end{subfigure} -\caption{\label{fig:introduction_control_decentralized}Decentralized control. Example of decentralized force feedback (\subref{fig:introduction_control_decentralized_schematic}), only three struts are shown for simplicity. Equivalent block diagram (\subref{fig:introduction_control_decentralized_diagram}), the controller is then diagonal.} -\end{figure} - -\paragraph{Position and Pointing Control} - -Control based on position sensors. -Wanted position is generally expressed in the cartesian frame. - -Sensors can be: -\begin{itemize} -\item In the frame of the struts (LVDT, Encoder, Strain gauges): usually decentralized control (Figure \ref{fig:introduction_control_decentralized_diagram}) -\item External sensors: centralized -\end{itemize} - -When using external sensors, a decoupling strategy is usually employed (Figure \ref{fig:introduction_control_decoupling}): -\begin{itemize} -\item Jacobian matrices: frame of the struts or cartesian frame -\item Modal control -\item Singular Value Decomposition -\item Multivariable control: LQG, H-Infinity (Figure \ref{fig:introduction_control_mimo}) -\end{itemize} - -From \cite{thayer02_six_axis_vibrat_isolat_system}: -\begin{quote} -Experimental closed-loop control results using the hexapod have shown that controllers designed using a decentralized single-strut design work well when compared to full multivariable methodologies. -\end{quote} - - -\begin{figure}[htbp] -\begin{subfigure}{0.33\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_control_mimo.png} -\end{center} -\subcaption{\label{fig:introduction_control_mimo} Multivariable Control} -\end{subfigure} -\begin{subfigure}{0.66\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_control_decoupling.png} -\end{center} -\subcaption{\label{fig:introduction_control_decoupling} Decoupling Control} -\end{subfigure} -\caption{\label{fig:introduction_control_mimo_vs_decoupling}Two strategies to control a multi-inputs-multi-outputs system. Use of a multivariable controller (\subref{fig:introduction_control_mimo}), or first decouple the plant with matrices, and then designing several single-input-single-output controllers (\subref{fig:introduction_control_decoupling})} -\end{figure} +\subsubsection{Predictive Design / Mechatronics approach} \begin{itemize} -\item Explain the Jacobian matrix -\end{itemize} - -When decoupling using the Jacobian matrix, the control can be performed in the frame of the struts (Figure \ref{fig:introduction_control_centralized_struts}) or in the cartesian frame (Figure \ref{fig:introduction_control_centralized_cartesian}). - -\begin{figure}[htbp] -\begin{subfigure}{0.95\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_control_centralized_struts.png} -\end{center} -\subcaption{\label{fig:introduction_control_centralized_struts} Control in the frame of the struts} -\end{subfigure} - -\bigskip -\begin{subfigure}{0.95\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_control_centralized_cartesian.png} -\end{center} -\subcaption{\label{fig:introduction_control_centralized_cartesian} Control in the cartesian frame} -\end{subfigure} -\caption{\label{fig:introduction_control_centralized}Two centralized control strategies. Express the position error in the frame of the struts and design one controller for each strut (\subref{fig:introduction_control_centralized_struts}). Design one controller for each direction, and then map the forces and torques to each struts (\subref{fig:introduction_control_centralized_cartesian}).} -\end{figure} - -\paragraph{Use of Multiple Sensors} - -Often, both vibration control and position control is wanted. -In that case, the use of multiple sensors can lead to improved performances. - -Sensors: +\item The performances of the system will depend on many factors: \begin{itemize} -\item collocated force (load cell) sensors -\item collocated accelerometer -\item displacement (eddy current) +\item sensors +\item actuators +\item mechanical design +\item achievable bandwidth \end{itemize} - -Several strategies can be employed: +\item Need to evaluate the different concepts, and predict the performances to guide the design +\item The goal is to design, built and test this system such that it work as expected the first time. +Very costly system, so must be correct. +\item \textbf{Challenge}: \begin{itemize} -\item HAC-LAC \cite{geng95_intel_contr_system_multip_degree,wang16_inves_activ_vibrat_isolat_stewar,li01_simul_vibrat_isolat_point_contr,pu11_six_degree_of_freed_activ,xie17_model_contr_hybrid_passiv_activ} -\item Sensor Fusion \cite{tjepkema12_activ_ph,tjepkema12_sensor_fusion_activ_vibrat_isolat_precis_equip,hauge04_sensor_contr_space_based_six} -\item Two Sensor control: \cite{hauge04_sensor_contr_space_based_six,tjepkema12_activ_ph} +\item Proper design methodology +\item Have accurate models to be able to compare different concepts +\item Converge to a solution that gives the wanted level of performance +\end{itemize} \end{itemize} - -Comparison between ``two sensor control'' and ``sensor fusion'' is given in \cite{beijen14_two_sensor_contr_activ_vibrat}. - -\begin{figure}[htbp] -\begin{subfigure}{0.48\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_architecture_hac_lac.png} -\end{center} -\subcaption{\label{fig:introduction_architecture_hac_lac} HAC-LAC} -\end{subfigure} -\begin{subfigure}{0.48\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_architecture_two_sensor_control.png} -\end{center} -\subcaption{\label{fig:introduction_architecture_two_sensor_control} Two Sensor Control} -\end{subfigure} - -\bigskip -\begin{subfigure}{0.95\textwidth} -\begin{center} -\includegraphics[scale=1,scale=1]{figs/introduction_architecture_sensor_fusion.png} -\end{center} -\subcaption{\label{fig:introduction_architecture_sensor_fusion} Sensor Fusion} -\end{subfigure} -\caption{\label{fig:introduction_control_multiple_sensors}Different control strategies when using multiple sensors. High Authority Control / Low Authority Control (\subref{fig:introduction_architecture_hac_lac}). Sensor Fusion (\subref{fig:introduction_architecture_sensor_fusion}). Two-Sensor Control (\subref{fig:introduction_architecture_two_sensor_control})} -\end{figure} - \chapter{Original Contributions} -This thesis proposes several contributions in the fields of Control, Mechatronics Design and Experimental validation. +In order to address the challenges associated with the development of the Nano Active Stabilization Systems, this thesis proposes several original contributions in the fields of Control, Mechatronics Design and Experimental validation. +\subsubsection{6DoF vibration control of a rotating platform} -\paragraph{Active Damping of rotating mechanical systems using Integral Force Feedback} +Long stroke / short stroke architectures are usually limited to 1DoF or 2DoF. +It is here extended to 6DoF. -\cite{dehaeze20_activ_dampin_rotat_platf_integ_force_feedb,dehaeze21_activ_dampin_rotat_platf_using} -\begin{quote} -This paper investigates the use of Integral Force Feedback (IFF) for the active damping of rotating mechanical systems. -Guaranteed stability, typical benefit of IFF, is lost as soon as the system is rotating due to gyroscopic effects. -To overcome this issue, two modifications of the classical IFF control scheme are proposed. -The first consists of slightly modifying the control law while the second consists of adding springs in parallel with the force sensors. -Conditions for stability and optimal parameters are derived. -The results reveal that, despite their different implementations, both modified IFF control scheme have almost identical damping authority on the suspension modes. -\end{quote} +The active platform will not only compensate for errors of the rotation stage, but also of all other stages. -\paragraph{Design of complementary filters using \(\mathcal{H}_\infty\) Synthesis and sensor fusion} +To the author's knowledge, the use of a continuously rotating stewart platform for vibration control has not been proved in the literature. +\subsubsection{Mechatronics design approach} -\cite{dehaeze19_compl_filter_shapin_using_synth} -\cite{verma20_virtual_sensor_fusion_high_precis_contr} -\cite{tsang22_optim_sensor_fusion_method_activ} +For the design of the NASS, a rigorous mechatronics design approach was conducted. +\cite{dehaeze18_sampl_stabil_for_tomog_exper,dehaeze21_mechat_approac_devel_nano_activ_stabil_system} + +While not new, this approach is here applied from start to finish: \begin{itemize} -\item Several uses (link to some papers). -\item For the NASS, they could be use to further improve the robustness of the system. +\item From first concepts using basic models, to concept validation using mode accurate models +\item Detailed design phase: models were used to optimize each individual components +\item Experimental phase: models were still found to have great use. +For instance to better understand the observed behavior, and also to optimize the implemented control strategy. \end{itemize} -\paragraph{Multi-body simulations with reduced order flexible bodies obtained by FEA} +The use of dynamical models were used all along the development. -\cite{brumund21_multib_simul_reduc_order_flexib_bodies_fea} +This document, being written chronologically: +\begin{itemize} +\item Make clear how each models can be useful during different parts of the project +\item Clearly show how each design decision are based on facts / clear conclusions extracted from the models +\item While the developed system is quite specific for the presented application, it shows the effectiveness of this design approach +\end{itemize} + +I hope this document can make a small contribution in the adoption of the mechatronics approach for the design of future end-station and synchrotron instrumentation. +\subsubsection{Multi-body simulations with reduced order flexible bodies obtained by FEA} + +One of the key tool that were used Combined multi-body / FEA techniques and experimental validation on a Stewart platform containing amplified piezoelectric actuators Super-element of amplified piezoelectric actuator / combined multibody-FEA technique, experimental validation on an amplified piezoelectric actuator and further validated on a complete stewart platform -\begin{quote} -We considered sub-components in the multi-body model as \emph{reduced order flexible bodies} representing the component’s modal behaviour with reduced mass and stiffness matrices obtained from finite element analysis (FEA) models. -These matrices were created from FEA models via modal reduction techniques, more specifically the \emph{component mode synthesis} (CMS). -This makes this design approach a combined multibody-FEA technique. -We validated the technique with a test bench that confirmed the good modelling capabilities using reduced order flexible body models obtained from FEA for an amplified piezoelectric actuator (APA). -\end{quote} - -\paragraph{Robustness by design} - +While not new: \begin{itemize} -\item Design of a Stewart platform and associated control architecture that is robust to large plant uncertainties due to large variety of payload and experimental conditions. -\item Instead of relying on complex controller synthesis (such as \(\mathcal{H}_\infty\) synthesis or \(\mu\text{-synthesis}\)) to guarantee the robustness and performance. -\item The approach here is to choose an adequate architecture (mechanics, sensors, actuators) such that controllers are robust by nature. -\item Example: collocated actuator/sensor pair => controller can easily be made robust -\item This is done by using models and using HAC-LAC architecture +\item Experimentally validated with both an amplified piezoelectric actuator as well as a flexible joint +\item It proved to be a very useful tool for the design/optimisation of components that have to be integrated in a larger system +\item Believed to be quite useful for the development of future mechatronics instrumentation \end{itemize} -\paragraph{Mechatronics design} +Subject of one publication \cite{brumund21_multib_simul_reduc_order_flexib_bodies_fea} +Further detailed in Section [\ldots{}]. +\subsubsection{Control Robustness by design} -Conduct a rigorous mechatronics design approach for a nano active stabilization system -\cite{dehaeze18_sampl_stabil_for_tomog_exper,dehaeze21_mechat_approac_devel_nano_activ_stabil_system} - -Approach from start to finish: +One of the main challenge is to design a system that is robust for all the experimental conditions: \begin{itemize} -\item From first concepts using basic models, to concept validation -\item Detailed design phase -\item Experimental phase +\item various rotational velocities used +\item payload used can weight up to 50kg \end{itemize} -Complete design with clear choices based on models. -Such approach, while not new, is here applied -This can be used for the design of future end-stations. +Instead of relying on complex controller synthesis (such as \(\mathcal{H}_\infty\) synthesis or \(\mu\text{-synthesis}\)) to guarantee the robustness and performance, the approach was to: +\begin{itemize} +\item Choose an adequate architecture (mechanics, sensors, actuators) such that controllers are robust by nature +\item An example is the use of collocated actuator/sensor pairs, such that controller stability can be guaranteed using passivity principles +\item To make informed choices on the chosen architecture: +\begin{itemize} +\item different ways to combine sensors (HAC-LAC, sensors fusion, two sensor control) were evaluated +\item different decoupling strategy were compared +\end{itemize} +Such discussion, presented in Section [\ldots{}] ,were found to be lacking in the literature. +\end{itemize} +\subsubsection{Active Damping of rotating mechanical systems using Integral Force Feedback} -\begin{figure}[htbp] -\centering -\includegraphics[scale=1,width=\linewidth]{figs/nass_mechatronics_approach.png} -\caption{\label{fig:introduction_nass_mechatronics_approach}Overview of the mechatronic approach used for the Nano-Active-Stabilization-System} -\end{figure} +During the conceptual design, it was found the guaranteed stability of the active damping technique called ``Integral Force Feedback'' (IFF), is lost for rotating platforms as is the case for the NASS. -\paragraph{6DoF vibration control of a rotating platform} +To overcome this issue, two modifications of the classical IFF control scheme are proposed. +The first consists of slightly modifying the control law while the second consists of adding springs in parallel with the force sensors. +Conditions for stability and optimal parameters are derived. -Vibration control in 5DoF of a rotating stage -To the author's knowledge, the use of a continuously rotating stewart platform for vibration control has not been proved in the literature. +\cite{dehaeze20_activ_dampin_rotat_platf_integ_force_feedb,dehaeze21_activ_dampin_rotat_platf_using} +\subsubsection{Design of complementary filters using \(\mathcal{H}_\infty\) Synthesis} -\paragraph{Experimental validation of the Nano Active Stabilization System} +One way to combine sensors is to use ``sensor fusion''. +In such case, complementary filters are used to filter and combine the sensors. -Demonstration of the improvement of the the positioning accuracy of a complex multi DoF (the micro-station) by several orders of magnitude (Section \ldots{}) using \ldots{} +A method for designing such filter is proposed \cite{dehaeze19_compl_filter_shapin_using_synth}, that allows to shape the complementary filters norm, which allows to guarantee the performance of the fusion. +This was latter applied for optimal sensor fusion in gravitational wave detectors \cite{tsang22_optim_sensor_fusion_method_activ}. +The design strategy is discussed in Section [\ldots{}]. +The use of such complementary filters for feedback control can also lead to interesting control architecture, as discussed in \cite{verma20_virtual_sensor_fusion_high_precis_contr} and further developed in Section [\ldots{}]. +\subsubsection{Experimental validation of the Nano Active Stabilization System} +The positioning performances of the Nano Active Stabilization System is experimentally evaluated/demonstrated on the ID31 beamline. + +The positioning accuracy of the micro-station is effectively improved from the \textasciitilde{}10um down to \textasciitilde{}100nm while performing experiments. +Robustness to sample's mass, and different experimental conditions are also verified. + +This therefore lead to a very versatile end-station, with high payload capabilities and nano-meter accuracy, allowing for full exploitation of the x-ray beam and associated instrumentation. + +To the author's knowledge, this is the first time such active platform is used to improve the accuracy of a positioning stage in 5DoF. \chapter{Thesis Outline - Mechatronics Design Approach} -\begin{figure}[htbp] -\centering -\includegraphics[scale=1,width=\linewidth]{figs/introduction_overview_chapters.png} -\caption{\label{fig:introduction_overview_chapters}Overview of the sections} -\end{figure} - -This thesis +This thesis is organized: \begin{itemize} -\item has a structure that follows the mechatronics design approach +\item to follow the mechatronics development approach, i.e. it is chronologically written. \end{itemize} -Is structured in three chapters that corresponds to the three mains parts of the proposed mechatronics approach. - +The three chapters corresponds to the three mains parts of the proposed mechatronics approach. A brief overview of these three chapters is given bellow. - -\paragraph{Conceptual design development} +\subsubsection{Conceptual design development} \begin{itemize} -\item Start with simple models for witch trade offs can be easily understood (uniaxial) +\item Talk about dynamic error budgeting +\item Talk about used model +\end{itemize} + +The goal of this first chapter is to find a concept: +\begin{itemize} +\item that will provide the wanted performances with high level of confidence +\item As such system is costly, a mechatronics design approach is used \cite{monkhorst04_dynam_error_budget} to be able to design the system ``right the first time'': +\begin{itemize} +\item When the system is finally build, its performance level should satisfy the specifications. +\item No significant changes are allowed in the post design phase. +\item Because of this, the designer wants to be able to predict the performance of the system a-priori and gain insight in the performance limiting factors of the system. +\end{itemize} +\end{itemize} + +To do so: +\begin{itemize} +\item Dynamical models are used, with included disturbances, feedback architecture, etc.. +These models can be used to perform simulations, evaluate performances +\item General idea is to start with very simple models, that can easily be understood (mass-spring-damper uniaxial model) \item Increase the model complexity if important physical phenomenon are to be modelled (cf the rotating model) \item Only when better understanding of the physical effects in play, and only if required, go for higher model complexity (here multi-body model) -\item The system concept and main characteristics should be extracted from the different models and validated with closed-loop simulations with the most accurate model -\item Once the concept is validated, the chosen concept can be design in mode details \end{itemize} -\paragraph{Detailed design} - +To better understand the performance limitations, for different models, \emph{dynamic error budgeting} \cite{monkhorst04_dynam_error_budget,okyay16_mechat_desig_dynam_contr_metrol} are performed. +It consists of: \begin{itemize} -\item During this detailed design phase, models are refined from the obtained CAD and using FEM -\item The models are used to assists the design and to optimize each element based on dynamical analysis and closed-loop simulations -\item The requirements for all the associated instrumentation can be determined from a dynamical noise budgeting -\item After converging to a detailed design that give acceptable performance based on the models, the different parts can be ordered and the experimental phase begins +\item Disturbance and noise signals are modeled by their spectral content, i.e. by their power spectral density (PSD) +\item The effect of each error sources on the final error, while the feedback control is active, can be easily estimated +\item Therefore, the effect that have the greatest impact on the achievable performance can be easily spotted and improved +\item Different concepts can be compared +\item This tool is therefore key in better understanding the main limitations, and guide the determination of the best concept, early in the project. \end{itemize} -\paragraph{Experimental validation} +This chapter concludes with accurate time domain simulations of a tomography experiment, validating the developed concept. +\subsubsection{Detailed design} \begin{itemize} -\item It is advised that the important characteristics of the different elements are evaluated individually +\item In the second chapter, the chosen concept can be design in more details. +\item First, the architecture and geometry of the active platform is optimized. +\item Then, key components of the active platform, such as the flexible joints and the actuators, are optimized using the combined multi-body / FEA design approach. +\item This allowed to optimize the components using very accurate models (thanks to FEA), while still being able to integrate these components in the complete multi-body model of the NASS for time domain simulations. +\item Different aspects of the control of the NASS, such as the optimal use of multiple sensors integrated in the active platform, the best adapted decoupling strategy and the design of the robust controller, are then discussed. +\item The requirements for all the associated instrumentation (digital to analog converters, analog to digital converters, voltage amplifiers, relative motion sensors) are chosen based on dynamic error budgeting. +Using such approach, it was made sure that none of these instrumentation will limit the overall performance of the system. +\item This chapter concludes with a presentation of the final design of the active platform. +\end{itemize} +\subsubsection{Experimental validation} + +After converging to a detailed design that give acceptable performance based on the models, the different parts were ordered and the experimental phase began. + +Instead of directly assembling the active platform and testing it on the ID31 micro-station, a systematic approach was followed to characterize individual components. +\begin{itemize} +\item Therefore, actuators and flexible joints were individual characterized. +This allowed to update the model of these components, and obtained a more accurate model of the active platform Systematic validation/refinement of models with experimental measurements -\item The obtained characteristics can be used to refine the models -\item Then, an accurate model of the system is obtained which can be used during experimental tests (for control synthesis for instance) +\item Actuators and flexible joints were combined to form the active ``struts'' of the active platform. +These struts are also characterized +\item Once the active platform were assembled, its dynamical model were found to over a very good match with the measured dynamics. +\item This chapter conclude with the experimental tests on the ID31 micro-station of the complete NASS. +\item Various scientific experiments are performed, such as tomography, and with various payload masses, to access the performances of the final system. \end{itemize} - - \printbibliography[heading=bibintoc,title={Bibliography}] \end{document}