Change the reference to the correct hexapod leg

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Thomas Dehaeze 2019-12-12 13:18:03 +01:00
parent 72c9afb29f
commit 6af5593c16
7 changed files with 74 additions and 115 deletions

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@ -3,7 +3,7 @@
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<!-- 2019-12-11 mer. 17:33 -->
<!-- 2019-12-12 jeu. 13:17 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>Computation of the Positioning Error with respect to the nano-hexapod</title>
@ -283,33 +283,32 @@ for the JavaScript code in this tag.
<h2>Table of Contents</h2>
<div id="text-table-of-contents">
<ul>
<li><a href="#orge221809">1. How do we measure the position of the sample with respect to the granite</a></li>
<li><a href="#org1148842">2. Verify that the function to compute the reference pose is correct</a>
<li><a href="#org063baa6">1. Verify that the function to compute the reference pose is correct</a>
<ul>
<li><a href="#orgb069429">2.1. Prepare the Simulation</a></li>
<li><a href="#org79597b7">2.2. Verify that the pose of the sample is the same as the computed one</a></li>
<li><a href="#org9dd1626">2.3. Conclusion</a></li>
<li><a href="#org0e8368a">1.1. Prepare the Simulation</a></li>
<li><a href="#orgf8068b5">1.2. Verify that the pose of the sample is the same as the computed one</a></li>
<li><a href="#org48dc703">1.3. Conclusion</a></li>
</ul>
</li>
<li><a href="#org54d1c35">3. Verify that the function to convert the position error in the frame fixed to the nano-hexapod is working</a>
<li><a href="#org5998e7b">2. Verify that the function to convert the position error in the frame fixed to the nano-hexapod is working</a>
<ul>
<li><a href="#org07d2e9e">3.1. Prepare the Simulation</a></li>
<li><a href="#orgd5c310c">3.2. Compute the wanted pose of the sample in the NASS Base from the metrology and the reference</a></li>
<li><a href="#org109338f">3.3. Verify that be imposing the error motion on the nano-hexapod, we indeed have zero error at the end</a></li>
<li><a href="#orga75d3ed">3.4. Conclusion</a></li>
<li><a href="#orgb013c86">2.1. Prepare the Simulation</a></li>
<li><a href="#orgcc5a377">2.2. Compute the wanted pose of the sample in the NASS Base from the metrology and the reference</a></li>
<li><a href="#orgb86542e">2.3. Verify that be imposing the error motion on the nano-hexapod, we indeed have zero error at the end</a></li>
<li><a href="#org0336147">2.4. Conclusion</a></li>
</ul>
</li>
<li><a href="#orge995172">4. Verify that we are able to compensate the errors using the nano-hexapod</a></li>
<li><a href="#org91e7b22">3. Verify that we are able to compensate the errors using the nano-hexapod</a></li>
</ul>
</div>
</div>
<p>
The global measurement and control schematic is shown in figure <a href="#orgf0b4232">1</a>.
The global measurement and control schematic is shown in figure <a href="#orgc057460">1</a>.
</p>
<div id="orgf0b4232" class="figure">
<div id="orgc057460" class="figure">
<p><img src="figs/control-schematic-nass.png" alt="control-schematic-nass.png" />
</p>
<p><span class="figure-number">Figure 1: </span>Global Control Schematic for the Station</p>
@ -323,6 +322,7 @@ In this document, we develop and verify that the two green blocs are working.
We suppose that we are able to measure perfectly the position of the sample with respect to the granite.
This means that we do not care about the bloc "Compute Sample Position w.r.t. Granite" that makes the transformation from the interferometer measurements to the position of the sample.
We suppose that we can directly measure perfectly the position of the sample with respect to the granite.
This is actually done with a "transform sensor block" that outputs the x-y-z translation of the sample with respect to the granite as well as the rotation matrix that maps the granite frame to the sample frame.
</p>
<p>
@ -330,59 +330,29 @@ Also, all the stages can be perfectly positioned.
</p>
<p>
In section <a href="#org44336a1">2</a>, we verify that the function developed to compute the wanted pose (translation and orientation) of the sample with respect to the granite can be determined from the wanted position of each stage (translation stage, tilt stage, spindle and micro-hexapod). This corresponds to the bloc "Compute Wanted Sample Position w.r.t. Granite" in figure <a href="#orgf0b4232">1</a>.
In section <a href="#orgc8a514e">1</a>, we verify that the function developed to compute the wanted pose (translation and orientation) of the sample with respect to the granite can be determined from the wanted position of each stage (translation stage, tilt stage, spindle and micro-hexapod). This corresponds to the bloc "Compute Wanted Sample Position w.r.t. Granite" in figure <a href="#orgc057460">1</a>.
To do so, we impose a perfect displacement and all the stage, we perfectly measure the position of the sample with respect to the granite, and we verify that this measured position corresponds to the computed wanted pose of the sample.
</p>
<p>
Then, in section <a href="#org9f1c3ad">3</a>, we introduce some positioning error in the micro-station's stages.
The positioning error of the sample expressed with respect to the granite frame (the one measured) is expressed in a frame connected to the NASS top platform (corresponding to the green bloc "Compute Sample Position Error w.r.t. NASS" in figure <a href="#orgf0b4232">1</a>).
Then, in section <a href="#org87c9e04">2</a>, we introduce some positioning error in the micro-station's stages.
The positioning error of the sample expressed with respect to the granite frame (the one measured) is expressed in a frame connected to the NASS top platform (corresponding to the green bloc "Compute Sample Position Error w.r.t. NASS" in figure <a href="#orgc057460">1</a>).
Then, we move the NASS such that it compensate for the positioning error that are expressed in the frame of the NASS, and we verify that the positioning error of the sample is well compensated.
</p>
<div id="outline-container-orge221809" class="outline-2">
<h2 id="orge221809"><span class="section-number-2">1</span> How do we measure the position of the sample with respect to the granite</h2>
<div id="outline-container-org063baa6" class="outline-2">
<h2 id="org063baa6"><span class="section-number-2">1</span> Verify that the function to compute the reference pose is correct</h2>
<div class="outline-text-2" id="text-1">
<p>
<a id="org38f1c05"></a>
A transform sensor block gives the translation and orientation of the follower frame with respect to the base frame.
</p>
<p>
The base frame is fixed to the granite and located at the initial sample location that defines the zero position.
</p>
<p>
The follower frame is attached to the sample (or more precisely to the reflector).
</p>
<p>
The outputs of the transform sensor are:
</p>
<ul class="org-ul">
<li>the 3 translations x, y and z in meter</li>
<li>the <b>rotation matrix</b> \(\bm{R}\) that permits to rotate the base frame into the follower frame.</li>
</ul>
<p>
We can then determine extract other orientation conventions such that Euler angles or screw axis.
</p>
</div>
</div>
<div id="outline-container-org1148842" class="outline-2">
<h2 id="org1148842"><span class="section-number-2">2</span> Verify that the function to compute the reference pose is correct</h2>
<div class="outline-text-2" id="text-2">
<p>
<a id="org44336a1"></a>
<a id="orgc8a514e"></a>
</p>
<p>
The goal here is to perfectly move the station and verify that there is no mismatch between the metrology measurement and the computation of the reference pose.
</p>
</div>
<div id="outline-container-orgb069429" class="outline-3">
<h3 id="orgb069429"><span class="section-number-3">2.1</span> Prepare the Simulation</h3>
<div class="outline-text-3" id="text-2-1">
<div id="outline-container-org0e8368a" class="outline-3">
<h3 id="org0e8368a"><span class="section-number-3">1.1</span> Prepare the Simulation</h3>
<div class="outline-text-3" id="text-1-1">
<p>
We load the configuration.
</p>
@ -439,7 +409,8 @@ We setup the reference path to be constant.
<span class="org-string">'Dn_pos'</span>, <span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">1e</span><span class="org-type">-</span><span class="org-highlight-numbers-number">3</span>; <span class="org-highlight-numbers-number">2e</span><span class="org-type">-</span><span class="org-highlight-numbers-number">3</span>; <span class="org-highlight-numbers-number">3e</span><span class="org-type">-</span><span class="org-highlight-numbers-number">3</span>; <span class="org-highlight-numbers-number">1</span><span class="org-type">*</span><span class="org-constant">pi</span><span class="org-type">/</span><span class="org-highlight-numbers-number">180</span>; <span class="org-highlight-numbers-number">0</span>; <span class="org-highlight-numbers-number">1</span><span class="org-type">*</span><span class="org-constant">pi</span><span class="org-type">/</span><span class="org-highlight-numbers-number">180</span><span class="org-rainbow-delimiters-depth-2">]</span> ...<span class="org-comment"> % Initial position [m,m,m,rad,rad,rad] of the top platform</span>
<span class="org-rainbow-delimiters-depth-1">)</span>;
initializeReferences<span class="org-rainbow-delimiters-depth-1">(</span>opts<span class="org-rainbow-delimiters-depth-1">)</span>;
initializeReferences<span class="org-rainbow-delimiters-depth-1">()</span>;
</pre>
</div>
@ -450,9 +421,9 @@ No position error for now (perfect positioning).
<pre class="src src-matlab">Dye = <span class="org-highlight-numbers-number">0</span>; <span class="org-comment">% [m]</span>
Rye = <span class="org-highlight-numbers-number">0</span>; <span class="org-comment">% [rad]</span>
Rze = <span class="org-highlight-numbers-number">0</span>; <span class="org-comment">% [rad]</span>
Dhe = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">6</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span>; <span class="org-comment">% [m,rad]</span>
Dhle = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">6</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span>; <span class="org-comment">% [m]</span>
Dne = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">6</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span>; <span class="org-comment">% [m,rad]</span>
Dhe = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">6</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span>; <span class="org-comment">% [m,m,m,rad,rad,rad]</span>
Dhle = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">6</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span>; <span class="org-comment">% [m,m,m,m,m,m]</span>
Dne = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">6</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span>; <span class="org-comment">% [m,m,m,rad,rad,rad]</span>
</pre>
</div>
@ -460,15 +431,15 @@ Dne = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org
And we run the simulation.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-simulink-keyword">sim</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'simscape/sim_nano_station_metrology.slx'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
<pre class="src src-matlab"><span class="org-matlab-simulink-keyword">sim</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'sim_nano_station_metrology'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
</div>
</div>
<div id="outline-container-org79597b7" class="outline-3">
<h3 id="org79597b7"><span class="section-number-3">2.2</span> Verify that the pose of the sample is the same as the computed one</h3>
<div class="outline-text-3" id="text-2-2">
<div id="outline-container-orgf8068b5" class="outline-3">
<h3 id="orgf8068b5"><span class="section-number-3">1.2</span> Verify that the pose of the sample is the same as the computed one</h3>
<div class="outline-text-3" id="text-1-2">
<p>
Let's denote:
</p>
@ -531,21 +502,21 @@ WTr<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlig
<pre class="example">
WTr(1:3, 4, end)-WTm(1:3, 4, end)
ans =
1.8027246362351e-14
1.40408518145563e-14
6.93889390390723e-17
-8.22065745307538e-15
-1.74128279577812e-15
-8.3754490393689e-16
WTr(1:3, 1:3, end)'*WTm(1:3, 1:3, end)-eye(3)
ans =
1.59872115546023e-14 -1.56629266848118e-14 -3.71230823859037e-16
1.56742023874057e-14 1.59872115546023e-14 -2.12330153459561e-15
-1.14144804719274e-15 -5.51642065360625e-16 9.28146448586631e-14
2.66453525910038e-15 6.12072360433062e-16 2.08519182823275e-16
-6.12072360433062e-16 2.66453525910038e-15 3.83905507244395e-16
-2.08519182823275e-16 -3.83905507244395e-16 2.66453525910038e-15
</pre>
</div>
</div>
<div id="outline-container-org9dd1626" class="outline-3">
<h3 id="org9dd1626"><span class="section-number-3">2.3</span> Conclusion</h3>
<div class="outline-text-3" id="text-2-3">
<div id="outline-container-org48dc703" class="outline-3">
<h3 id="org48dc703"><span class="section-number-3">1.3</span> Conclusion</h3>
<div class="outline-text-3" id="text-1-3">
<div class="important">
<p>
We are able to compute the wanted position and orientation of the sample.
@ -557,11 +528,11 @@ Both the measurement and the theory gives the same result.
</div>
</div>
<div id="outline-container-org54d1c35" class="outline-2">
<h2 id="org54d1c35"><span class="section-number-2">3</span> Verify that the function to convert the position error in the frame fixed to the nano-hexapod is working</h2>
<div class="outline-text-2" id="text-3">
<div id="outline-container-org5998e7b" class="outline-2">
<h2 id="org5998e7b"><span class="section-number-2">2</span> Verify that the function to convert the position error in the frame fixed to the nano-hexapod is working</h2>
<div class="outline-text-2" id="text-2">
<p>
<a id="org9f1c3ad"></a>
<a id="org87c9e04"></a>
</p>
<p>
We now introduce some positioning error in the stage.
@ -572,9 +543,9 @@ This will induce a global positioning error of the sample with respect to the de
We want to verify that we are able to measure this positioning error and convert it in the frame attached to the Nano-hexapod.
</p>
</div>
<div id="outline-container-org07d2e9e" class="outline-3">
<h3 id="org07d2e9e"><span class="section-number-3">3.1</span> Prepare the Simulation</h3>
<div class="outline-text-3" id="text-3-1">
<div id="outline-container-orgb013c86" class="outline-3">
<h3 id="orgb013c86"><span class="section-number-3">2.1</span> Prepare the Simulation</h3>
<div class="outline-text-3" id="text-2-1">
<p>
We load the configuration.
</p>
@ -650,15 +621,15 @@ Dne = zeros<span class="org-rainbow-delimiters-depth-1">(</span><span class="org
And we run the simulation.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-simulink-keyword">sim</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'simscape/sim_nano_station_metrology.slx'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
<pre class="src src-matlab"><span class="org-matlab-simulink-keyword">sim</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'sim_nano_station_metrology'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
</div>
</div>
<div id="outline-container-orgd5c310c" class="outline-3">
<h3 id="orgd5c310c"><span class="section-number-3">3.2</span> Compute the wanted pose of the sample in the NASS Base from the metrology and the reference</h3>
<div class="outline-text-3" id="text-3-2">
<div id="outline-container-orgcc5a377" class="outline-3">
<h3 id="orgcc5a377"><span class="section-number-3">2.2</span> Compute the wanted pose of the sample in the NASS Base from the metrology and the reference</h3>
<div class="outline-text-3" id="text-2-2">
<p>
Now that we have introduced some positioning error, the computed wanted pose and the measured pose will not be the same.
</p>
@ -792,9 +763,9 @@ Rz = <span class="org-rainbow-delimiters-depth-1">[</span>cos<span class="org-ra
</div>
</div>
<div id="outline-container-org109338f" class="outline-3">
<h3 id="org109338f"><span class="section-number-3">3.3</span> Verify that be imposing the error motion on the nano-hexapod, we indeed have zero error at the end</h3>
<div class="outline-text-3" id="text-3-3">
<div id="outline-container-orgb86542e" class="outline-3">
<h3 id="orgb86542e"><span class="section-number-3">2.3</span> Verify that be imposing the error motion on the nano-hexapod, we indeed have zero error at the end</h3>
<div class="outline-text-3" id="text-2-3">
<p>
We now keep the wanted pose but we impose a displacement of the nano hexapod corresponding to the measured position error.
</p>
@ -808,7 +779,7 @@ initializeReferences<span class="org-rainbow-delimiters-depth-1">(</span>opts<sp
And we run the simulation.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-matlab-simulink-keyword">sim</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'simscape/sim_nano_station_metrology.slx'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
<pre class="src src-matlab"><span class="org-matlab-simulink-keyword">sim</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'sim_nano_station_metrology'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
@ -887,9 +858,9 @@ Verify that the pose error is small.
</div>
</div>
<div id="outline-container-orga75d3ed" class="outline-3">
<h3 id="orga75d3ed"><span class="section-number-3">3.4</span> Conclusion</h3>
<div class="outline-text-3" id="text-3-4">
<div id="outline-container-org0336147" class="outline-3">
<h3 id="org0336147"><span class="section-number-3">2.4</span> Conclusion</h3>
<div class="outline-text-3" id="text-2-4">
<div class="important">
<p>
Indeed, we are able to convert the position error in the frame of the NASS and then compensate these errors with the NASS.
@ -900,13 +871,13 @@ Indeed, we are able to convert the position error in the frame of the NASS and t
</div>
</div>
<div id="outline-container-orge995172" class="outline-2">
<h2 id="orge995172"><span class="section-number-2">4</span> Verify that we are able to compensate the errors using the nano-hexapod</h2>
<div id="outline-container-org91e7b22" class="outline-2">
<h2 id="org91e7b22"><span class="section-number-2">3</span> Verify that we are able to compensate the errors using the nano-hexapod</h2>
</div>
</div>
<div id="postamble" class="status">
<p class="author">Author: Dehaeze Thomas</p>
<p class="date">Created: 2019-12-11 mer. 17:33</p>
<p class="date">Created: 2019-12-12 jeu. 13:17</p>
<p class="validation"><a href="http://validator.w3.org/check?uri=referer">Validate</a></p>
</div>
</body>

View File

@ -53,6 +53,7 @@ In this document, we develop and verify that the two green blocs are working.
We suppose that we are able to measure perfectly the position of the sample with respect to the granite.
This means that we do not care about the bloc "Compute Sample Position w.r.t. Granite" that makes the transformation from the interferometer measurements to the position of the sample.
We suppose that we can directly measure perfectly the position of the sample with respect to the granite.
This is actually done with a "transform sensor block" that outputs the x-y-z translation of the sample with respect to the granite as well as the rotation matrix that maps the granite frame to the sample frame.
Also, all the stages can be perfectly positioned.
@ -63,20 +64,6 @@ Then, in section [[sec:compute_pos_error]], we introduce some positioning error
The positioning error of the sample expressed with respect to the granite frame (the one measured) is expressed in a frame connected to the NASS top platform (corresponding to the green bloc "Compute Sample Position Error w.r.t. NASS" in figure [[fig:control-schematic-nass]]).
Then, we move the NASS such that it compensate for the positioning error that are expressed in the frame of the NASS, and we verify that the positioning error of the sample is well compensated.
* How do we measure the position of the sample with respect to the granite
<<sec:measurement_principle>>
A transform sensor block gives the translation and orientation of the follower frame with respect to the base frame.
The base frame is fixed to the granite and located at the initial sample location that defines the zero position.
The follower frame is attached to the sample (or more precisely to the reflector).
The outputs of the transform sensor are:
- the 3 translations x, y and z in meter
- the *rotation matrix* $\bm{R}$ that permits to rotate the base frame into the follower frame.
We can then determine extract other orientation conventions such that Euler angles or screw axis.
* Verify that the function to compute the reference pose is correct
<<sec:compute_reference>>
** Introduction :ignore:
@ -145,7 +132,8 @@ We setup the reference path to be constant.
'Dn_pos', [1e-3; 2e-3; 3e-3; 1*pi/180; 0; 1*pi/180] ... % Initial position [m,m,m,rad,rad,rad] of the top platform
);
initializeReferences(opts);
initializeReferences();
#+end_src
No position error for now (perfect positioning).
@ -153,9 +141,9 @@ No position error for now (perfect positioning).
Dye = 0; % [m]
Rye = 0; % [rad]
Rze = 0; % [rad]
Dhe = zeros(6,1); % [m,rad]
Dhle = zeros(6,1); % [m]
Dne = zeros(6,1); % [m,rad]
Dhe = zeros(6,1); % [m,m,m,rad,rad,rad]
Dhle = zeros(6,1); % [m,m,m,m,m,m]
Dne = zeros(6,1); % [m,m,m,rad,rad,rad]
#+end_src
And we run the simulation.
@ -208,14 +196,14 @@ Or are least:
#+begin_example
WTr(1:3, 4, end)-WTm(1:3, 4, end)
ans =
1.8027246362351e-14
1.40408518145563e-14
6.93889390390723e-17
-8.22065745307538e-15
-1.74128279577812e-15
-8.3754490393689e-16
WTr(1:3, 1:3, end)'*WTm(1:3, 1:3, end)-eye(3)
ans =
1.59872115546023e-14 -1.56629266848118e-14 -3.71230823859037e-16
1.56742023874057e-14 1.59872115546023e-14 -2.12330153459561e-15
-1.14144804719274e-15 -5.51642065360625e-16 9.28146448586631e-14
2.66453525910038e-15 6.12072360433062e-16 2.08519182823275e-16
-6.12072360433062e-16 2.66453525910038e-15 3.83905507244395e-16
-2.08519182823275e-16 -3.83905507244395e-16 2.66453525910038e-15
#+end_example
** Conclusion