diff --git a/phd-thesis.org b/phd-thesis.org index 7a4f9d5..98b17e2 100644 --- a/phd-thesis.org +++ b/phd-thesis.org @@ -315,12 +315,41 @@ The research presented in this manuscript has been possible thanks to the Fonds :UNNUMBERED: t :END: +The conceptual design of the Nano Active Stabilization System (NASS) follows a methodical progression from simple to more accurate modeling approaches, as illustrated in Figure\nbsp{}ref:fig:chapter1_overview. + #+name: fig:chapter1_overview -#+caption: Figure caption +#+caption: Overview of the conceptual design development. The approach evolves from simplified analytical models to a multi-body model tuned from experimental modal analysis. It is concluded by closed-loop simulations of tomography experiments, validating the conceptual design. #+attr_org: :width 800px #+attr_latex: :width \linewidth [[file:figs/chapter1_overview.png]] +The design process begins with a uniaxial model, presented in Section\nbsp{}ref:sec:uniaxial, which provides initial insights into fundamental challenges associated with this complex system. +This simplified representation focuses exclusively on the vertical direction—having the most stringent requirements—though similar conclusions were drawn from analyses of other axes. +Despite its simplicity, this uniaxial model proves valuable for testing initial control strategies and, more importantly, for evaluating how the active platform stiffness affects overall system performance. + +Building upon these findings, Section\nbsp{}ref:sec:rotating introduces the rotational aspect through a three-degree-of-freedom model. +This new model allows to study the gyroscopic effects induced by the spindle's continuous rotation—a distinctive characteristic of the NASS. +The investigation reveals that these gyroscopic effects have more impact on softer active platforms, creating significant challenges for stability and control. + +As the investigation progressed, the need for a more accurate representation of the micro-station dynamics became increasingly evident. +To construct such a model, a comprehensive modal analysis was conducted, as detailed in Section\nbsp{}ref:sec:modal. +This experimental modal analysis confirmed the complex nature of the micro-station dynamics while validating that each stage behaves predominantly as a rigid body within the frequency range of interest—thus supporting the subsequent development of a multi-body model. + +Section\nbsp{}ref:sec:ustation presents the development of this multi-body model for the micro-station. +Parameters were meticulously tuned to match measured compliance characteristics, and disturbance sources were carefully modeled based on experimental data. +This refined model was then validated through simulations of scientific experiments, demonstrating its accuracy in representing the micro-station behavior under typical operating conditions. + +For the active stabilization stage, the Stewart platform architecture was selected after careful evaluation of various options. +Section\nbsp{}ref:sec:nhexa examines the kinematic and dynamic properties of this parallel manipulator, exploring its control challenges and developing appropriate control strategies for implementation within the NASS. +The multi-body modeling approach facilitated the seamless integration of the nano-hexapod with the micro-station model. + +Finally, Section\nbsp{}ref:sec:nass validates the NASS concept through closed-loop simulations of tomography experiments. +These simulations incorporate realistic disturbance sources, confirming the viability of the proposed design approach and control strategies. + +This progressive approach, beginning with easily comprehensible simplified models, proved instrumental in developing a thorough understanding of the physical phenomena at play. +By methodically increasing model complexity only as needed, the design process converged efficiently toward a concept capable of delivering the required performance levels. +The confidence gained through this systematic investigation provides a solid foundation for transitioning to the detailed design phase, which will be addressed in the following chapter. + ** Uni-axial Model <> *** Introduction :ignore: