Add Relative Active Damping study

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Thomas Dehaeze 2021-11-30 11:45:05 +01:00
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@ -3,7 +3,7 @@
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<!-- 2021-11-30 mar. 11:26 -->
<!-- 2021-11-30 mar. 11:44 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<title>DCM - Dynamical Multi-Body Model</title>
<meta name="author" content="Dehaeze Thomas" />
@ -39,39 +39,41 @@
<h2>Table of Contents</h2>
<div id="text-table-of-contents" role="doc-toc">
<ul>
<li><a href="#orgeeaccd1">1. System Kinematics</a>
<li><a href="#orgcb7822a">1. System Kinematics</a>
<ul>
<li><a href="#org82f10d2">1.1. Bragg Angle</a></li>
<li><a href="#orgea96012">1.2. Kinematics (111 Crystal)</a>
<li><a href="#orgc4b429c">1.1. Bragg Angle</a></li>
<li><a href="#orga30e667">1.2. Kinematics (111 Crystal)</a>
<ul>
<li><a href="#org1ea22c7">1.2.1. Interferometers - 111 Crystal</a></li>
<li><a href="#orgdcb38e9">1.2.2. Piezo - 111 Crystal</a></li>
<li><a href="#org390c6c1">1.2.1. Interferometers - 111 Crystal</a></li>
<li><a href="#org4c00d94">1.2.2. Piezo - 111 Crystal</a></li>
</ul>
</li>
<li><a href="#org7beb5f6">1.3. Save Kinematics</a></li>
<li><a href="#org82434d5">1.3. Save Kinematics</a></li>
</ul>
</li>
<li><a href="#orgc562e49">2. Open Loop System Identification</a>
<li><a href="#orgd95f56d">2. Open Loop System Identification</a>
<ul>
<li><a href="#org461a35a">2.1. Identification</a></li>
<li><a href="#org32530ab">2.2. Plant in the frame of the fastjacks</a></li>
<li><a href="#org831ac4a">2.3. Plant in the frame of the crystal</a></li>
<li><a href="#org49ca34a">2.1. Identification</a></li>
<li><a href="#org170173c">2.2. Plant in the frame of the fastjacks</a></li>
<li><a href="#orge372095">2.3. Plant in the frame of the crystal</a></li>
</ul>
</li>
<li><a href="#org6a67c7c">3. Active Damping Plant (Strain gauges)</a>
<li><a href="#org00855cb">3. Active Damping Plant (Strain gauges)</a>
<ul>
<li><a href="#org59bf8d2">3.1. Identification</a></li>
<li><a href="#org6886aa9">3.1. Identification</a></li>
<li><a href="#orgd1754c8">3.2. Relative Active Damping</a></li>
<li><a href="#orgf6e5d1c">3.3. Damped Plant</a></li>
</ul>
</li>
<li><a href="#org98018d6">4. Active Damping Plant (Force Sensors)</a>
<li><a href="#org3953e07">4. Active Damping Plant (Force Sensors)</a>
<ul>
<li><a href="#orgf3d05f6">4.1. Identification</a></li>
<li><a href="#org2c7747a">4.2. Controller - Root Locus</a></li>
<li><a href="#org44eaa41">4.3. Damped Plant</a></li>
<li><a href="#orgd9ea17f">4.4. Save</a></li>
<li><a href="#org243bdc3">4.1. Identification</a></li>
<li><a href="#orga2bc3f0">4.2. Controller - Root Locus</a></li>
<li><a href="#org63d6a74">4.3. Damped Plant</a></li>
<li><a href="#org8c22e6e">4.4. Save</a></li>
</ul>
</li>
<li><a href="#org93a00ff">5. HAC-LAC (IFF) architecture</a></li>
<li><a href="#org053c75c">5. HAC-LAC (IFF) architecture</a></li>
</ul>
</div>
</div>
@ -87,22 +89,22 @@ In this document, a Simscape (.e.g. multi-body) model of the ESRF Double Crystal
It is structured as follow:
</p>
<ul class="org-ul">
<li>Section <a href="#org2e89cff">1</a>: the kinematics of the DCM is presented, and Jacobian matrices which are used to solve the inverse and forward kinematics are computed.</li>
<li>Section <a href="#orgdd4a98d">2</a>: the system dynamics is identified in the absence of control.</li>
<li>Section <a href="#orgdeb64e7">3</a>: it is studied whether if the strain gauges fixed to the piezoelectric actuators can be used to actively damp the plant.</li>
<li>Section <a href="#org624796e">4</a>: piezoelectric force sensors are added in series with the piezoelectric actuators and are used to actively damp the plant using the Integral Force Feedback (IFF) control strategy.</li>
<li>Section <a href="#orga8f0b23">5</a>: the High Authority Control - Low Authority Control (HAC-LAC) strategy is tested on the Simscape model.</li>
<li>Section <a href="#org0fd3e9f">1</a>: the kinematics of the DCM is presented, and Jacobian matrices which are used to solve the inverse and forward kinematics are computed.</li>
<li>Section <a href="#orgd4eb6dd">2</a>: the system dynamics is identified in the absence of control.</li>
<li>Section <a href="#orgdb80cfb">3</a>: it is studied whether if the strain gauges fixed to the piezoelectric actuators can be used to actively damp the plant.</li>
<li>Section <a href="#org8e736b1">4</a>: piezoelectric force sensors are added in series with the piezoelectric actuators and are used to actively damp the plant using the Integral Force Feedback (IFF) control strategy.</li>
<li>Section <a href="#orga68bafc">5</a>: the High Authority Control - Low Authority Control (HAC-LAC) strategy is tested on the Simscape model.</li>
</ul>
<div id="outline-container-orgeeaccd1" class="outline-2">
<h2 id="orgeeaccd1"><span class="section-number-2">1.</span> System Kinematics</h2>
<div id="outline-container-orgcb7822a" class="outline-2">
<h2 id="orgcb7822a"><span class="section-number-2">1.</span> System Kinematics</h2>
<div class="outline-text-2" id="text-1">
<p>
<a id="org2e89cff"></a>
<a id="org0fd3e9f"></a>
</p>
</div>
<div id="outline-container-org82f10d2" class="outline-3">
<h3 id="org82f10d2"><span class="section-number-3">1.1.</span> Bragg Angle</h3>
<div id="outline-container-orgc4b429c" class="outline-3">
<h3 id="orgc4b429c"><span class="section-number-3">1.1.</span> Bragg Angle</h3>
<div class="outline-text-3" id="text-1-1">
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Tested bragg angles</span>
@ -118,7 +120,7 @@ dz = d_off<span class="org-builtin">./</span>(2<span class="org-builtin">*</span
</div>
<div id="org41541e2" class="figure">
<div id="org122820c" class="figure">
<p><img src="figs/jack_motion_bragg_angle.png" alt="jack_motion_bragg_angle.png" />
</p>
<p><span class="figure-number">Figure 1: </span>Jack motion as a function of Bragg angle</p>
@ -136,34 +138,34 @@ dz = d_off<span class="org-builtin">./</span>(2<span class="org-builtin">*</span
</div>
</div>
<div id="outline-container-orgea96012" class="outline-3">
<h3 id="orgea96012"><span class="section-number-3">1.2.</span> Kinematics (111 Crystal)</h3>
<div id="outline-container-orga30e667" class="outline-3">
<h3 id="orga30e667"><span class="section-number-3">1.2.</span> Kinematics (111 Crystal)</h3>
<div class="outline-text-3" id="text-1-2">
<p>
The reference frame is taken at the center of the 111 second crystal.
</p>
</div>
<div id="outline-container-org1ea22c7" class="outline-4">
<h4 id="org1ea22c7"><span class="section-number-4">1.2.1.</span> Interferometers - 111 Crystal</h4>
<div id="outline-container-org390c6c1" class="outline-4">
<h4 id="org390c6c1"><span class="section-number-4">1.2.1.</span> Interferometers - 111 Crystal</h4>
<div class="outline-text-4" id="text-1-2-1">
<p>
Three interferometers are pointed to the bottom surface of the 111 crystal.
</p>
<p>
The position of the measurement points are shown in Figure <a href="#org2ba7ed7">2</a> as well as the origin where the motion of the crystal is computed.
The position of the measurement points are shown in Figure <a href="#org7147d17">2</a> as well as the origin where the motion of the crystal is computed.
</p>
<div id="org2ba7ed7" class="figure">
<div id="org7147d17" class="figure">
<p><img src="figs/sensor_111_crystal_points.png" alt="sensor_111_crystal_points.png" />
</p>
<p><span class="figure-number">Figure 2: </span>Bottom view of the second crystal 111. Position of the measurement points.</p>
</div>
<p>
The inverse kinematics consisting of deriving the interferometer measurements from the motion of the crystal (see Figure <a href="#orga898030">3</a>):
The inverse kinematics consisting of deriving the interferometer measurements from the motion of the crystal (see Figure <a href="#org8e47ad4">3</a>):
</p>
\begin{equation}
\begin{bmatrix}
@ -177,7 +179,7 @@ d_z \\ r_y \\ r_x
\end{equation}
<div id="orga898030" class="figure">
<div id="org8e47ad4" class="figure">
<p><img src="figs/schematic_sensor_jacobian_inverse_kinematics.png" alt="schematic_sensor_jacobian_inverse_kinematics.png" />
</p>
<p><span class="figure-number">Figure 3: </span>Inverse Kinematics - Interferometers</p>
@ -185,7 +187,7 @@ d_z \\ r_y \\ r_x
<p>
From the Figure <a href="#org2ba7ed7">2</a>, the inverse kinematics can be solved as follow (for small motion):
From the Figure <a href="#org7147d17">2</a>, the inverse kinematics can be solved as follow (for small motion):
</p>
\begin{equation}
\bm{J}_{s,111}
@ -205,7 +207,7 @@ J_s_111 = [1, 0.07, <span class="org-builtin">-</span>0.015
</pre>
</div>
<table id="org798edde" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<table id="org8c13b9a" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 1:</span> Sensor Jacobian \(\bm{J}_{s,111}\)</caption>
<colgroup>
@ -237,7 +239,7 @@ J_s_111 = [1, 0.07, <span class="org-builtin">-</span>0.015
</table>
<p>
The forward kinematics is solved by inverting the Jacobian matrix (see Figure <a href="#org1633a04">4</a>).
The forward kinematics is solved by inverting the Jacobian matrix (see Figure <a href="#org700c4d4">4</a>).
</p>
\begin{equation}
\begin{bmatrix}
@ -251,13 +253,13 @@ x_1 \\ x_2 \\ x_3
\end{equation}
<div id="org1633a04" class="figure">
<div id="org700c4d4" class="figure">
<p><img src="figs/schematic_sensor_jacobian_forward_kinematics.png" alt="schematic_sensor_jacobian_forward_kinematics.png" />
</p>
<p><span class="figure-number">Figure 4: </span>Forward Kinematics - Interferometers</p>
</div>
<table id="org1bb9156" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<table id="org65d7338" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 2:</span> Inverse of the sensor Jacobian \(\bm{J}_{s,111}^{-1}\)</caption>
<colgroup>
@ -290,15 +292,15 @@ x_1 \\ x_2 \\ x_3
</div>
</div>
<div id="outline-container-orgdcb38e9" class="outline-4">
<h4 id="orgdcb38e9"><span class="section-number-4">1.2.2.</span> Piezo - 111 Crystal</h4>
<div id="outline-container-org4c00d94" class="outline-4">
<h4 id="org4c00d94"><span class="section-number-4">1.2.2.</span> Piezo - 111 Crystal</h4>
<div class="outline-text-4" id="text-1-2-2">
<p>
The location of the actuators with respect with the center of the 111 second crystal are shown in Figure <a href="#org67c7fa3">5</a>.
The location of the actuators with respect with the center of the 111 second crystal are shown in Figure <a href="#orgd329873">5</a>.
</p>
<div id="org67c7fa3" class="figure">
<div id="orgd329873" class="figure">
<p><img src="figs/actuator_jacobian_111_points.png" alt="actuator_jacobian_111_points.png" />
</p>
<p><span class="figure-number">Figure 5: </span>Location of actuators with respect to the center of the 111 second crystal (bottom view)</p>
@ -319,14 +321,14 @@ d_z \\ r_y \\ r_x
\end{equation}
<div id="org6dc1eec" class="figure">
<div id="orga74633d" class="figure">
<p><img src="figs/schematic_actuator_jacobian_inverse_kinematics.png" alt="schematic_actuator_jacobian_inverse_kinematics.png" />
</p>
<p><span class="figure-number">Figure 6: </span>Inverse Kinematics - Actuators</p>
</div>
<p>
Based on the geometry in Figure <a href="#org67c7fa3">5</a>, we obtain:
Based on the geometry in Figure <a href="#orgd329873">5</a>, we obtain:
</p>
\begin{equation}
\bm{J}_{a,111}
@ -346,7 +348,7 @@ J_a_111 = [1, 0.14, <span class="org-builtin">-</span>0.1525
</pre>
</div>
<table id="org987e530" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<table id="org363311b" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 3:</span> Actuator Jacobian \(\bm{J}_{a,111}\)</caption>
<colgroup>
@ -392,13 +394,13 @@ d_{u_r} \\ d_{u_h} \\ d_{d}
\end{equation}
<div id="orga69da79" class="figure">
<div id="orgeeec18d" class="figure">
<p><img src="figs/schematic_actuator_jacobian_forward_kinematics.png" alt="schematic_actuator_jacobian_forward_kinematics.png" />
</p>
<p><span class="figure-number">Figure 7: </span>Forward Kinematics - Actuators for 111 crystal</p>
</div>
<table id="orgb6769cb" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<table id="org19c3313" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 4:</span> Inverse of the actuator Jacobian \(\bm{J}_{a,111}^{-1}\)</caption>
<colgroup>
@ -432,8 +434,8 @@ d_{u_r} \\ d_{u_h} \\ d_{d}
</div>
</div>
<div id="outline-container-org7beb5f6" class="outline-3">
<h3 id="org7beb5f6"><span class="section-number-3">1.3.</span> Save Kinematics</h3>
<div id="outline-container-org82434d5" class="outline-3">
<h3 id="org82434d5"><span class="section-number-3">1.3.</span> Save Kinematics</h3>
<div class="outline-text-3" id="text-1-3">
<div class="org-src-container">
<pre class="src src-matlab">save(<span class="org-string">'mat/dcm_kinematics.mat'</span>, <span class="org-string">'J_a_111'</span>, <span class="org-string">'J_s_111'</span>)
@ -443,15 +445,15 @@ d_{u_r} \\ d_{u_h} \\ d_{d}
</div>
</div>
<div id="outline-container-orgc562e49" class="outline-2">
<h2 id="orgc562e49"><span class="section-number-2">2.</span> Open Loop System Identification</h2>
<div id="outline-container-orgd95f56d" class="outline-2">
<h2 id="orgd95f56d"><span class="section-number-2">2.</span> Open Loop System Identification</h2>
<div class="outline-text-2" id="text-2">
<p>
<a id="orgdd4a98d"></a>
<a id="orgd4eb6dd"></a>
</p>
</div>
<div id="outline-container-org461a35a" class="outline-3">
<h3 id="org461a35a"><span class="section-number-3">2.1.</span> Identification</h3>
<div id="outline-container-org49ca34a" class="outline-3">
<h3 id="org49ca34a"><span class="section-number-3">2.1.</span> Identification</h3>
<div class="outline-text-3" id="text-2-1">
<p>
Let&rsquo;s considered the system \(\bm{G}(s)\) with:
@ -462,11 +464,11 @@ Let&rsquo;s considered the system \(\bm{G}(s)\) with:
</ul>
<p>
It is schematically shown in Figure <a href="#org7c50fa9">8</a>.
It is schematically shown in Figure <a href="#org52a4b7c">8</a>.
</p>
<div id="org7c50fa9" class="figure">
<div id="org52a4b7c" class="figure">
<p><img src="figs/schematic_system_inputs_outputs.png" alt="schematic_system_inputs_outputs.png" />
</p>
<p><span class="figure-number">Figure 8: </span>Dynamical system with inputs and outputs</p>
@ -508,8 +510,8 @@ State-space model with 3 outputs, 3 inputs, and 24 states.
</div>
</div>
<div id="outline-container-org32530ab" class="outline-3">
<h3 id="org32530ab"><span class="section-number-3">2.2.</span> Plant in the frame of the fastjacks</h3>
<div id="outline-container-org170173c" class="outline-3">
<h3 id="org170173c"><span class="section-number-3">2.2.</span> Plant in the frame of the fastjacks</h3>
<div class="outline-text-3" id="text-2-2">
<div class="org-src-container">
<pre class="src src-matlab">load(<span class="org-string">'mat/dcm_kinematics.mat'</span>);
@ -517,11 +519,11 @@ State-space model with 3 outputs, 3 inputs, and 24 states.
</div>
<p>
Using the forward and inverse kinematics, we can computed the dynamics from piezo forces to axial motion of the 3 fastjacks (see Figure <a href="#orga3837b0">9</a>).
Using the forward and inverse kinematics, we can computed the dynamics from piezo forces to axial motion of the 3 fastjacks (see Figure <a href="#orgf9b4903">9</a>).
</p>
<div id="orga3837b0" class="figure">
<div id="orgf9b4903" class="figure">
<p><img src="figs/schematic_jacobian_frame_fastjack.png" alt="schematic_jacobian_frame_fastjack.png" />
</p>
<p><span class="figure-number">Figure 9: </span>Use of Jacobian matrices to obtain the system in the frame of the fastjacks</p>
@ -542,7 +544,7 @@ The DC gain of the new system shows that the system is well decoupled at low fre
</pre>
</div>
<table id="org06bdfa0" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<table id="org19e4a7e" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 5:</span> DC gain of the plant in the frame of the fast jacks \(\bm{G}_{\text{fj}}\)</caption>
<colgroup>
@ -574,17 +576,17 @@ The DC gain of the new system shows that the system is well decoupled at low fre
</table>
<p>
The bode plot of \(\bm{G}_{\text{fj}}(s)\) is shown in Figure <a href="#org4e62924">10</a>.
The bode plot of \(\bm{G}_{\text{fj}}(s)\) is shown in Figure <a href="#org6777e66">10</a>.
</p>
<div id="org4e62924" class="figure">
<div id="org6777e66" class="figure">
<p><img src="figs/bode_plot_plant_fj.png" alt="bode_plot_plant_fj.png" />
</p>
<p><span class="figure-number">Figure 10: </span>Bode plot of the diagonal and off-diagonal elements of the plant in the frame of the fast jacks</p>
</div>
<div class="important" id="org3ded063">
<div class="important" id="orgcdf2cc1">
<p>
Computing the system in the frame of the fastjack gives good decoupling at low frequency (until the first resonance of the system).
</p>
@ -593,11 +595,11 @@ Computing the system in the frame of the fastjack gives good decoupling at low f
</div>
</div>
<div id="outline-container-org831ac4a" class="outline-3">
<h3 id="org831ac4a"><span class="section-number-3">2.3.</span> Plant in the frame of the crystal</h3>
<div id="outline-container-orge372095" class="outline-3">
<h3 id="orge372095"><span class="section-number-3">2.3.</span> Plant in the frame of the crystal</h3>
<div class="outline-text-3" id="text-2-3">
<div id="org3adfc9a" class="figure">
<div id="org4377a93" class="figure">
<p><img src="figs/schematic_jacobian_frame_crystal.png" alt="schematic_jacobian_frame_crystal.png" />
</p>
<p><span class="figure-number">Figure 11: </span>Use of Jacobian matrices to obtain the system in the frame of the crystal</p>
@ -652,18 +654,18 @@ The main reason is that, as we map forces to the center of the 111 crystal and n
</div>
</div>
<div id="outline-container-org6a67c7c" class="outline-2">
<h2 id="org6a67c7c"><span class="section-number-2">3.</span> Active Damping Plant (Strain gauges)</h2>
<div id="outline-container-org00855cb" class="outline-2">
<h2 id="org00855cb"><span class="section-number-2">3.</span> Active Damping Plant (Strain gauges)</h2>
<div class="outline-text-2" id="text-3">
<p>
<a id="orgdeb64e7"></a>
<a id="orgdb80cfb"></a>
</p>
<p>
In this section, we wish to see whether if strain gauges fixed to the piezoelectric actuator can be used for active damping.
</p>
</div>
<div id="outline-container-org59bf8d2" class="outline-3">
<h3 id="org59bf8d2"><span class="section-number-3">3.1.</span> Identification</h3>
<div id="outline-container-org6886aa9" class="outline-3">
<h3 id="org6886aa9"><span class="section-number-3">3.1.</span> Identification</h3>
<div class="outline-text-3" id="text-3-1">
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Input/Output definition</span>
@ -671,13 +673,11 @@ clear io; io_i = 1;
<span class="org-matlab-cellbreak">%% Inputs</span>
<span class="org-comment-delimiter">% </span><span class="org-comment">Control Input {3x1} [N]</span>
io(io_i) = linio([mdl, <span class="org-string">'/u'</span>], 1, <span class="org-string">'openinput'</span>); io_i = io_i <span class="org-builtin">+</span> 1;
<span class="org-comment-delimiter">% </span><span class="org-comment">% Stepper Displacement {3x1} [m]</span>
<span class="org-comment-delimiter">% </span><span class="org-comment">io(io_i) = linio([mdl, '/d'], 1, 'openinput'); io_i = io_i + 1;</span>
io(io_i) = linio([mdl, <span class="org-string">'/control_system'</span>], 1, <span class="org-string">'openinput'</span>); io_i = io_i <span class="org-builtin">+</span> 1;
<span class="org-matlab-cellbreak">%% Outputs</span>
<span class="org-comment-delimiter">% </span><span class="org-comment">Strain Gauges {3x1} [m]</span>
io(io_i) = linio([mdl, <span class="org-string">'/sg'</span>], 1, <span class="org-string">'openoutput'</span>); io_i = io_i <span class="org-builtin">+</span> 1;
io(io_i) = linio([mdl, <span class="org-string">'/DCM'</span>], 2, <span class="org-string">'openoutput'</span>); io_i = io_i <span class="org-builtin">+</span> 1;
</pre>
</div>
@ -704,33 +704,128 @@ G_sg = linearize(mdl, io);
</colgroup>
<tbody>
<tr>
<td class="org-right">-1.4113e-13</td>
<td class="org-right">4.4443e-09</td>
<td class="org-right">1.0339e-13</td>
<td class="org-right">3.774e-14</td>
</tr>
<tr>
<td class="org-right">1.0339e-13</td>
<td class="org-right">-1.4113e-13</td>
<td class="org-right">4.4443e-09</td>
<td class="org-right">3.774e-14</td>
</tr>
<tr>
<td class="org-right">3.7792e-14</td>
<td class="org-right">3.7792e-14</td>
<td class="org-right">-7.5585e-14</td>
<td class="org-right">4.4444e-09</td>
</tr>
</tbody>
</table>
<div id="org72b48ee" class="figure">
<p><img src="figs/strain_gauge_plant_bode_plot.png" alt="strain_gauge_plant_bode_plot.png" />
</p>
<p><span class="figure-number">Figure 12: </span>Bode Plot of the transfer functions from piezoelectric forces to strain gauges measuremed displacements</p>
</div>
<div class="important" id="org070666c">
<p>
As the distance between the poles and zeros in Figure <a href="#org16f0105">15</a> is very small, little damping can be actively added using the strain gauges.
This will be confirmed using a Root Locus plot.
</p>
</div>
</div>
</div>
<div id="outline-container-org98018d6" class="outline-2">
<h2 id="org98018d6"><span class="section-number-2">4.</span> Active Damping Plant (Force Sensors)</h2>
<div id="outline-container-orgd1754c8" class="outline-3">
<h3 id="orgd1754c8"><span class="section-number-3">3.2.</span> Relative Active Damping</h3>
<div class="outline-text-3" id="text-3-2">
<div class="org-src-container">
<pre class="src src-matlab">Krad_g1 = eye(3)<span class="org-builtin">*</span>s<span class="org-builtin">/</span>(s<span class="org-builtin">^</span>2<span class="org-builtin">/</span>(2<span class="org-builtin">*</span><span class="org-matlab-math">pi</span><span class="org-builtin">*</span>500)<span class="org-builtin">^</span>2 <span class="org-builtin">+</span> 2<span class="org-builtin">*</span>s<span class="org-builtin">/</span>(2<span class="org-builtin">*</span><span class="org-matlab-math">pi</span><span class="org-builtin">*</span>500) <span class="org-builtin">+</span> 1);
</pre>
</div>
<p>
As can be seen in Figure <a href="#org16a4fc0">13</a>, very little damping can be added using relative damping strategy using strain gauges.
</p>
<div id="org16a4fc0" class="figure">
<p><img src="figs/relative_damping_root_locus.png" alt="relative_damping_root_locus.png" />
</p>
<p><span class="figure-number">Figure 13: </span>Root Locus for the relative damping control</p>
</div>
<div class="org-src-container">
<pre class="src src-matlab">Krad = <span class="org-builtin">-</span>g<span class="org-builtin">*</span>Krad_g1;
</pre>
</div>
</div>
</div>
<div id="outline-container-orgf6e5d1c" class="outline-3">
<h3 id="orgf6e5d1c"><span class="section-number-3">3.3.</span> Damped Plant</h3>
<div class="outline-text-3" id="text-3-3">
<p>
The controller is implemented on Simscape, and the damped plant is identified.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Input/Output definition</span>
clear io; io_i = 1;
<span class="org-matlab-cellbreak">%% Inputs</span>
<span class="org-comment-delimiter">% </span><span class="org-comment">Control Input {3x1} [N]</span>
io(io_i) = linio([mdl, <span class="org-string">'/control_system'</span>], 1, <span class="org-string">'input'</span>); io_i = io_i <span class="org-builtin">+</span> 1;
<span class="org-matlab-cellbreak">%% Outputs</span>
<span class="org-comment-delimiter">% </span><span class="org-comment">Force Sensor {3x1} [m]</span>
io(io_i) = linio([mdl, <span class="org-string">'/DCM'</span>], 1, <span class="org-string">'openoutput'</span>); io_i = io_i <span class="org-builtin">+</span> 1;
</pre>
</div>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% DCM Kinematics</span>
load(<span class="org-string">'mat/dcm_kinematics.mat'</span>);
</pre>
</div>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Identification of the Open Loop plant</span>
controller.type = 0; <span class="org-comment-delimiter">% </span><span class="org-comment">Open Loop</span>
G_ol = J_a_111<span class="org-builtin">*</span>inv(J_s_111)<span class="org-builtin">*</span>linearize(mdl, io);
G_ol.InputName = {<span class="org-string">'u_ur'</span>, <span class="org-string">'u_uh'</span>, <span class="org-string">'u_d'</span>};
G_ol.OutputName = {<span class="org-string">'d_ur'</span>, <span class="org-string">'d_uh'</span>, <span class="org-string">'d_d'</span>};
</pre>
</div>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Identification of the damped plant with Relative Active Damping</span>
controller.type = 2; <span class="org-comment-delimiter">% </span><span class="org-comment">RAD</span>
G_dp = J_a_111<span class="org-builtin">*</span>inv(J_s_111)<span class="org-builtin">*</span>linearize(mdl, io);
G_dp.InputName = {<span class="org-string">'u_ur'</span>, <span class="org-string">'u_uh'</span>, <span class="org-string">'u_d'</span>};
G_dp.OutputName = {<span class="org-string">'d_ur'</span>, <span class="org-string">'d_uh'</span>, <span class="org-string">'d_d'</span>};
</pre>
</div>
<div id="org908c24c" class="figure">
<p><img src="figs/comp_damp_undamped_plant_rad_bode_plot.png" alt="comp_damp_undamped_plant_rad_bode_plot.png" />
</p>
<p><span class="figure-number">Figure 14: </span>Bode plot of both the open-loop plant and the damped plant using relative active damping</p>
</div>
</div>
</div>
</div>
<div id="outline-container-org3953e07" class="outline-2">
<h2 id="org3953e07"><span class="section-number-2">4.</span> Active Damping Plant (Force Sensors)</h2>
<div class="outline-text-2" id="text-4">
<p>
<a id="org624796e"></a>
<a id="org8e736b1"></a>
</p>
<p>
Force sensors are added above the piezoelectric actuators.
@ -738,8 +833,8 @@ They can consists of a simple piezoelectric ceramic stack.
See for instance <a href="fleming10_integ_strain_force_feedb_high">fleming10_integ_strain_force_feedb_high</a>.
</p>
</div>
<div id="outline-container-orgf3d05f6" class="outline-3">
<h3 id="orgf3d05f6"><span class="section-number-3">4.1.</span> Identification</h3>
<div id="outline-container-org243bdc3" class="outline-3">
<h3 id="org243bdc3"><span class="section-number-3">4.1.</span> Identification</h3>
<div class="outline-text-3" id="text-4-1">
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Input/Output definition</span>
@ -798,16 +893,16 @@ G_fs = linearize(mdl, io);
</table>
<div id="org2468af2" class="figure">
<div id="org16f0105" class="figure">
<p><img src="figs/iff_plant_bode_plot.png" alt="iff_plant_bode_plot.png" />
</p>
<p><span class="figure-number">Figure 12: </span>Bode plot of IFF Plant</p>
<p><span class="figure-number">Figure 15: </span>Bode plot of IFF Plant</p>
</div>
</div>
</div>
<div id="outline-container-org2c7747a" class="outline-3">
<h3 id="org2c7747a"><span class="section-number-3">4.2.</span> Controller - Root Locus</h3>
<div id="outline-container-orga2bc3f0" class="outline-3">
<h3 id="orga2bc3f0"><span class="section-number-3">4.2.</span> Controller - Root Locus</h3>
<div class="outline-text-3" id="text-4-2">
<div class="org-src-container">
<pre class="src src-matlab">Kiff_g1 = eye(3)<span class="org-builtin">*</span>1<span class="org-builtin">/</span>(1 <span class="org-builtin">+</span> s<span class="org-builtin">/</span>2<span class="org-builtin">/</span><span class="org-matlab-math">pi</span><span class="org-builtin">/</span>20);
@ -815,10 +910,10 @@ G_fs = linearize(mdl, io);
</div>
<div id="orgac1f06c" class="figure">
<div id="org4041645" class="figure">
<p><img src="figs/iff_root_locus.png" alt="iff_root_locus.png" />
</p>
<p><span class="figure-number">Figure 13: </span>Root Locus plot for the IFF Control strategy</p>
<p><span class="figure-number">Figure 16: </span>Root Locus plot for the IFF Control strategy</p>
</div>
<div class="org-src-container">
@ -829,8 +924,8 @@ Kiff = g<span class="org-builtin">*</span>Kiff_g1;
</div>
</div>
<div id="outline-container-org44eaa41" class="outline-3">
<h3 id="org44eaa41"><span class="section-number-3">4.3.</span> Damped Plant</h3>
<div id="outline-container-org63d6a74" class="outline-3">
<h3 id="org63d6a74"><span class="section-number-3">4.3.</span> Damped Plant</h3>
<div class="outline-text-3" id="text-4-3">
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-cellbreak">%% Input/Output definition</span>
@ -871,13 +966,13 @@ G_dp.OutputName = {<span class="org-string">'d_ur'</span>, <span class="org-str
</div>
<div id="orge31be94" class="figure">
<div id="org8455151" class="figure">
<p><img src="figs/comp_damped_undamped_plant_iff_bode_plot.png" alt="comp_damped_undamped_plant_iff_bode_plot.png" />
</p>
<p><span class="figure-number">Figure 14: </span>Bode plot of both the open-loop plant and the damped plant using IFF</p>
<p><span class="figure-number">Figure 17: </span>Bode plot of both the open-loop plant and the damped plant using IFF</p>
</div>
<div class="important" id="org4a8fc3e">
<div class="important" id="orgebe4b09">
<p>
The Integral Force Feedback control strategy is very effective in damping the suspension modes of the DCM.
</p>
@ -886,8 +981,8 @@ The Integral Force Feedback control strategy is very effective in damping the su
</div>
</div>
<div id="outline-container-orgd9ea17f" class="outline-3">
<h3 id="orgd9ea17f"><span class="section-number-3">4.4.</span> Save</h3>
<div id="outline-container-org8c22e6e" class="outline-3">
<h3 id="org8c22e6e"><span class="section-number-3">4.4.</span> Save</h3>
<div class="outline-text-3" id="text-4-4">
<div class="org-src-container">
<pre class="src src-matlab">save(<span class="org-string">'mat/Kiff.mat'</span>, <span class="org-string">'Kiff'</span>);
@ -897,18 +992,18 @@ The Integral Force Feedback control strategy is very effective in damping the su
</div>
</div>
<div id="outline-container-org93a00ff" class="outline-2">
<h2 id="org93a00ff"><span class="section-number-2">5.</span> HAC-LAC (IFF) architecture</h2>
<div id="outline-container-org053c75c" class="outline-2">
<h2 id="org053c75c"><span class="section-number-2">5.</span> HAC-LAC (IFF) architecture</h2>
<div class="outline-text-2" id="text-5">
<p>
<a id="orga8f0b23"></a>
<a id="orga68bafc"></a>
</p>
</div>
</div>
</div>
<div id="postamble" class="status">
<p class="author">Author: Dehaeze Thomas</p>
<p class="date">Created: 2021-11-30 mar. 11:26</p>
<p class="date">Created: 2021-11-30 mar. 11:44</p>
</div>
</body>
</html>

View File

@ -738,13 +738,11 @@ clear io; io_i = 1;
%% Inputs
% Control Input {3x1} [N]
io(io_i) = linio([mdl, '/u'], 1, 'openinput'); io_i = io_i + 1;
% % Stepper Displacement {3x1} [m]
% io(io_i) = linio([mdl, '/d'], 1, 'openinput'); io_i = io_i + 1;
io(io_i) = linio([mdl, '/control_system'], 1, 'openinput'); io_i = io_i + 1;
%% Outputs
% Strain Gauges {3x1} [m]
io(io_i) = linio([mdl, '/sg'], 1, 'openoutput'); io_i = io_i + 1;
io(io_i) = linio([mdl, '/DCM'], 2, 'openoutput'); io_i = io_i + 1;
#+end_src
#+begin_src matlab
@ -762,12 +760,12 @@ dcgain(G_sg)
#+end_src
#+RESULTS:
| -1.4113e-13 | 1.0339e-13 | 3.774e-14 |
| 1.0339e-13 | -1.4113e-13 | 3.774e-14 |
| 3.7792e-14 | 3.7792e-14 | -7.5585e-14 |
| 4.4443e-09 | 1.0339e-13 | 3.774e-14 |
| 1.0339e-13 | 4.4443e-09 | 3.774e-14 |
| 3.7792e-14 | 3.7792e-14 | 4.4444e-09 |
#+begin_src matlab :exports none
%% Bode plot for the plant
%% Bode plot for the plant (strain gauge output)
figure;
tiledlayout(3, 1, 'TileSpacing', 'Compact', 'Padding', 'None');
@ -788,7 +786,8 @@ end
hold off;
set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
ylabel('Amplitude [m/N]'); set(gca, 'XTickLabel',[]);
legend('location', 'southwest', 'FontSize', 8, 'NumColumns', 2);
legend('location', 'southeast', 'FontSize', 8, 'NumColumns', 2);
ylim([1e-14, 1e-7]);
ax2 = nexttile;
hold on;
@ -800,12 +799,173 @@ set(gca, 'XScale', 'log'); set(gca, 'YScale', 'lin');
xlabel('Frequency [Hz]'); ylabel('Phase [deg]');
hold off;
yticks(-360:90:360);
ylim([-180, 180]);
ylim([-180, 0]);
linkaxes([ax1,ax2],'x');
xlim([freqs(1), freqs(end)]);
#+end_src
#+begin_src matlab :tangle no :exports results :results file replace
exportFig('figs/strain_gauge_plant_bode_plot.pdf', 'width', 'wide', 'height', 'tall');
#+end_src
#+name: fig:strain_gauge_plant_bode_plot
#+caption: Bode Plot of the transfer functions from piezoelectric forces to strain gauges measuremed displacements
#+RESULTS:
[[file:figs/strain_gauge_plant_bode_plot.png]]
#+begin_important
As the distance between the poles and zeros in Figure [[fig:iff_plant_bode_plot]] is very small, little damping can be actively added using the strain gauges.
This will be confirmed using a Root Locus plot.
#+end_important
** Relative Active Damping
#+begin_src matlab
Krad_g1 = eye(3)*s/(s^2/(2*pi*500)^2 + 2*s/(2*pi*500) + 1);
#+end_src
As can be seen in Figure [[fig:relative_damping_root_locus]], very little damping can be added using relative damping strategy using strain gauges.
#+begin_src matlab :exports none
%% Root Locus for IFF
gains = logspace(3, 8, 200);
figure;
hold on;
plot(real(pole(G_sg)), imag(pole(G_sg)), 'x', 'color', colors(1,:), ...
'DisplayName', '$g = 0$');
plot(real(tzero(G_sg)), imag(tzero(G_sg)), 'o', 'color', colors(1,:), ...
'HandleVisibility', 'off');
for g = gains
clpoles = pole(feedback(G_sg, g*Krad_g1, -1));
plot(real(clpoles), imag(clpoles), '.', 'color', colors(1,:), ...
'HandleVisibility', 'off');
end
% Optimal gain
g = 2e5;
clpoles = pole(feedback(G_sg, g*Krad_g1, -1));
plot(real(clpoles), imag(clpoles), 'x', 'color', colors(2,:), ...
'DisplayName', sprintf('$g=%.0e$', g));
hold off;
xlim([-6, 0]); ylim([0, 2700]);
xlabel('Real Part'); ylabel('Imaginary Part');
legend('location', 'northwest');
#+end_src
#+begin_src matlab :tangle no :exports results :results file replace
exportFig('figs/relative_damping_root_locus.pdf', 'width', 'wide', 'height', 'tall');
#+end_src
#+name: fig:relative_damping_root_locus
#+caption: Root Locus for the relative damping control
#+RESULTS:
[[file:figs/relative_damping_root_locus.png]]
#+begin_src matlab
Krad = -g*Krad_g1;
#+end_src
** Damped Plant
The controller is implemented on Simscape, and the damped plant is identified.
#+begin_src matlab
%% Input/Output definition
clear io; io_i = 1;
%% Inputs
% Control Input {3x1} [N]
io(io_i) = linio([mdl, '/control_system'], 1, 'input'); io_i = io_i + 1;
%% Outputs
% Force Sensor {3x1} [m]
io(io_i) = linio([mdl, '/DCM'], 1, 'openoutput'); io_i = io_i + 1;
#+end_src
#+begin_src matlab
%% DCM Kinematics
load('mat/dcm_kinematics.mat');
#+end_src
#+begin_src matlab
%% Identification of the Open Loop plant
controller.type = 0; % Open Loop
G_ol = J_a_111*inv(J_s_111)*linearize(mdl, io);
G_ol.InputName = {'u_ur', 'u_uh', 'u_d'};
G_ol.OutputName = {'d_ur', 'd_uh', 'd_d'};
#+end_src
#+begin_src matlab
%% Identification of the damped plant with Relative Active Damping
controller.type = 2; % RAD
G_dp = J_a_111*inv(J_s_111)*linearize(mdl, io);
G_dp.InputName = {'u_ur', 'u_uh', 'u_d'};
G_dp.OutputName = {'d_ur', 'd_uh', 'd_d'};
#+end_src
#+begin_src matlab :exports none
%% Comparison of the damped and undamped plant
figure;
tiledlayout(3, 1, 'TileSpacing', 'Compact', 'Padding', 'None');
ax1 = nexttile([2,1]);
hold on;
plot(freqs, abs(squeeze(freqresp(G_ol(1,1), freqs, 'Hz'))), ...
'DisplayName', 'd - OL');
plot(freqs, abs(squeeze(freqresp(G_ol(2,2), freqs, 'Hz'))), ...
'DisplayName', 'uh - OL');
plot(freqs, abs(squeeze(freqresp(G_ol(3,3), freqs, 'Hz'))), ...
'DisplayName', 'ur - OL');
set(gca,'ColorOrderIndex',1)
plot(freqs, abs(squeeze(freqresp(G_dp(1,1), freqs, 'Hz'))), '--', ...
'DisplayName', 'd - IFF');
plot(freqs, abs(squeeze(freqresp(G_dp(2,2), freqs, 'Hz'))), '--', ...
'DisplayName', 'uh - IFF');
plot(freqs, abs(squeeze(freqresp(G_dp(3,3), freqs, 'Hz'))), '--', ...
'DisplayName', 'ur - IFF');
for i = 1:2
for j = i+1:3
plot(freqs, abs(squeeze(freqresp(G_dp(i,j), freqs, 'Hz'))), 'color', [0, 0, 0, 0.2], ...
'HandleVisibility', 'off');
end
end
hold off;
set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
ylabel('Amplitude [m/N]'); set(gca, 'XTickLabel',[]);
legend('location', 'southeast', 'FontSize', 8, 'NumColumns', 2);
ylim([1e-12, 1e-6]);
ax2 = nexttile;
hold on;
plot(freqs, 180/pi*angle(squeeze(freqresp(G_ol(1,1), freqs, 'Hz'))));
plot(freqs, 180/pi*angle(squeeze(freqresp(G_ol(2,2), freqs, 'Hz'))));
plot(freqs, 180/pi*angle(squeeze(freqresp(G_ol(3,3), freqs, 'Hz'))));
set(gca,'ColorOrderIndex',1)
plot(freqs, 180/pi*angle(squeeze(freqresp(G_dp(1,1), freqs, 'Hz'))), '--');
plot(freqs, 180/pi*angle(squeeze(freqresp(G_dp(2,2), freqs, 'Hz'))), '--');
plot(freqs, 180/pi*angle(squeeze(freqresp(G_dp(3,3), freqs, 'Hz'))), '--');
hold off;
set(gca, 'XScale', 'log'); set(gca, 'YScale', 'lin');
xlabel('Frequency [Hz]'); ylabel('Phase [deg]');
hold off;
yticks(-360:90:360);
ylim([-180, 0]);
linkaxes([ax1,ax2],'x');
xlim([freqs(1), freqs(end)]);
#+end_src
#+begin_src matlab :tangle no :exports results :results file replace
exportFig('figs/comp_damp_undamped_plant_rad_bode_plot.pdf', 'width', 'wide', 'height', 'tall');
#+end_src
#+name: fig:comp_damp_undamped_plant_rad_bode_plot
#+caption: Bode plot of both the open-loop plant and the damped plant using relative active damping
#+RESULTS:
[[file:figs/comp_damp_undamped_plant_rad_bode_plot.png]]
* Active Damping Plant (Force Sensors)
:PROPERTIES:
:header-args:matlab+: :tangle matlab/dcm_active_damping_iff.m

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