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Thomas Dehaeze 2020-12-16 14:07:07 +01:00
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head> <head>
<!-- 2020-12-16 mer. 11:52 --> <!-- 2020-12-16 mer. 14:07 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" /> <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<title>Encoder Renishaw Vionic - Test Bench</title> <title>Encoder Renishaw Vionic - Test Bench</title>
<meta name="generator" content="Org mode" /> <meta name="generator" content="Org mode" />
@ -30,14 +30,15 @@
<h2>Table of Contents</h2> <h2>Table of Contents</h2>
<div id="text-table-of-contents"> <div id="text-table-of-contents">
<ul> <ul>
<li><a href="#orgc6d067f">1. Encoder Model</a></li> <li><a href="#org096db33">1. Encoder Model</a></li>
<li><a href="#org0b88c21">2. Test-Bench Description</a></li> <li><a href="#orga6d0b8e">2. Test-Bench Description</a></li>
<li><a href="#org4b5c31e">3. Measurement procedure</a></li> <li><a href="#orgfc138a6">3. Measurement procedure</a></li>
<li><a href="#org2a53463">4. Measurement Results</a></li> <li><a href="#orgcddc280">4. Measurement Results</a></li>
</ul> </ul>
</div> </div>
</div> </div>
<div class="note" id="org89964c6">
<p> <p>
You can find below the document of: You can find below the document of:
</p> </p>
@ -46,8 +47,23 @@ You can find below the document of:
<li><a href="doc/L-9517-9862-01-C_Data_sheet_RKLC_EN.pdf">Linear Scale</a></li> <li><a href="doc/L-9517-9862-01-C_Data_sheet_RKLC_EN.pdf">Linear Scale</a></li>
</ul> </ul>
<div id="outline-container-orgc6d067f" class="outline-2"> </div>
<h2 id="orgc6d067f"><span class="section-number-2">1</span> Encoder Model</h2>
<p>
We would like to characterize the encoder measurement system.
</p>
<p>
In particular, we would like to measure:
</p>
<ul class="org-ul">
<li>Bandwidth/dynamics of the sensor</li>
<li>Power Spectral Density of the measurement noise</li>
<li>Linearity/resolution of the sensor</li>
</ul>
<div id="outline-container-org096db33" class="outline-2">
<h2 id="org096db33"><span class="section-number-2">1</span> Encoder Model</h2>
<div class="outline-text-2" id="text-1"> <div class="outline-text-2" id="text-1">
<p> <p>
The Encoder is characterized by its dynamics \(G_m(s)\) from the &ldquo;true&rdquo; displacement \(y\) to measured displacement \(y_m\). The Encoder is characterized by its dynamics \(G_m(s)\) from the &ldquo;true&rdquo; displacement \(y\) to measured displacement \(y_m\).
@ -58,8 +74,12 @@ Ideally, this dynamics is constant over a wide frequency band with very small ph
It is also characterized by its measurement noise \(n\) that can be described by its Power Spectral Density (PSD). It is also characterized by its measurement noise \(n\) that can be described by its Power Spectral Density (PSD).
</p> </p>
<p>
The model of the encoder is shown in Figure <a href="#org8c743b3">1</a>.
</p>
<div id="org4dcd6f3" class="figure">
<div id="org8c743b3" class="figure">
<p><img src="figs/encoder-model-schematic.png" alt="encoder-model-schematic.png" /> <p><img src="figs/encoder-model-schematic.png" alt="encoder-model-schematic.png" />
</p> </p>
<p><span class="figure-number">Figure 1: </span>Model of the Encoder</p> <p><span class="figure-number">Figure 1: </span>Model of the Encoder</p>
@ -67,23 +87,33 @@ It is also characterized by its measurement noise \(n\) that can be described by
</div> </div>
</div> </div>
<div id="outline-container-org0b88c21" class="outline-2"> <div id="outline-container-orga6d0b8e" class="outline-2">
<h2 id="org0b88c21"><span class="section-number-2">2</span> Test-Bench Description</h2> <h2 id="orga6d0b8e"><span class="section-number-2">2</span> Test-Bench Description</h2>
<div class="outline-text-2" id="text-2">
<p>
To measure the noise \(n\) of the encoder, one can rigidly fix the head and the ruler together such that no motion should be measured.
Then, the measured signal \(y_m\) corresponds to the noise \(n\).
</p>
<p>
In order to measure the linearity, we have to compare the measured displacement with a reference sensor with a known linearity.
An interferometer or capacitive sensor should work.
An actuator should also be there so impose a displacement.
</p>
</div>
</div> </div>
<div id="outline-container-orgfc138a6" class="outline-2">
<div id="outline-container-org4b5c31e" class="outline-2"> <h2 id="orgfc138a6"><span class="section-number-2">3</span> Measurement procedure</h2>
<h2 id="org4b5c31e"><span class="section-number-2">3</span> Measurement procedure</h2>
</div> </div>
<div id="outline-container-orgcddc280" class="outline-2">
<div id="outline-container-org2a53463" class="outline-2"> <h2 id="orgcddc280"><span class="section-number-2">4</span> Measurement Results</h2>
<h2 id="org2a53463"><span class="section-number-2">4</span> Measurement Results</h2>
</div> </div>
</div> </div>
<div id="postamble" class="status"> <div id="postamble" class="status">
<p class="author">Author: Dehaeze Thomas</p> <p class="author">Author: Dehaeze Thomas</p>
<p class="date">Created: 2020-12-16 mer. 11:52</p> <p class="date">Created: 2020-12-16 mer. 14:07</p>
</div> </div>
</body> </body>
</html> </html>

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* Introduction :ignore: * Introduction :ignore:
#+begin_note
You can find below the document of: You can find below the document of:
- [[file:doc/L-9517-9678-05-A_Data_sheet_VIONiC_series_en.pdf][Vionic Encoder]] - [[file:doc/L-9517-9678-05-A_Data_sheet_VIONiC_series_en.pdf][Vionic Encoder]]
- [[file:doc/L-9517-9862-01-C_Data_sheet_RKLC_EN.pdf][Linear Scale]] - [[file:doc/L-9517-9862-01-C_Data_sheet_RKLC_EN.pdf][Linear Scale]]
#+end_note
We would like to characterize the encoder measurement system.
In particular, we would like to measure:
- Bandwidth/dynamics of the sensor
- Power Spectral Density of the measurement noise
- Linearity/resolution of the sensor
* Encoder Model * Encoder Model
The Encoder is characterized by its dynamics $G_m(s)$ from the "true" displacement $y$ to measured displacement $y_m$. The Encoder is characterized by its dynamics $G_m(s)$ from the "true" displacement $y$ to measured displacement $y_m$.
@ -52,6 +61,8 @@ Ideally, this dynamics is constant over a wide frequency band with very small ph
It is also characterized by its measurement noise $n$ that can be described by its Power Spectral Density (PSD). It is also characterized by its measurement noise $n$ that can be described by its Power Spectral Density (PSD).
The model of the encoder is shown in Figure [[fig:encoder-model-schematic]].
#+begin_src latex :file encoder-model-schematic.pdf #+begin_src latex :file encoder-model-schematic.pdf
\begin{tikzpicture} \begin{tikzpicture}
\node[block] (G) at (0,0){$G_m(s)$}; \node[block] (G) at (0,0){$G_m(s)$};
@ -76,8 +87,13 @@ It is also characterized by its measurement noise $n$ that can be described by i
* Test-Bench Description * Test-Bench Description
To measure the noise $n$ of the encoder, one can rigidly fix the head and the ruler together such that no motion should be measured.
Then, the measured signal $y_m$ corresponds to the noise $n$.
In order to measure the linearity, we have to compare the measured displacement with a reference sensor with a known linearity.
An interferometer or capacitive sensor should work.
An actuator should also be there so impose a displacement.
* Measurement procedure * Measurement procedure
* Measurement Results * Measurement Results