110 lines
4.1 KiB
Org Mode
110 lines
4.1 KiB
Org Mode
#+TITLE:Effect of the rotation of the Slip-Ring
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:DRAWER:
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#+STARTUP: overview
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#+HTML_HEAD: <link rel="stylesheet" type="text/css" href="../css/htmlize.css"/>
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#+HTML_HEAD: <link rel="stylesheet" type="text/css" href="../css/readtheorg.css"/>
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#+HTML_HEAD: <link rel="stylesheet" type="text/css" href="../css/zenburn.css"/>
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#+HTML_HEAD: <script type="text/javascript" src="../js/jquery.min.js"></script>
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#+HTML_HEAD: <script type="text/javascript" src="../js/bootstrap.min.js"></script>
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#+HTML_HEAD: <script type="text/javascript" src="../js/jquery.stickytableheaders.min.js"></script>
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#+HTML_HEAD: <script type="text/javascript" src="../js/readtheorg.js"></script>
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#+PROPERTY: header-args:matlab :session *MATLAB*
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#+PROPERTY: header-args:matlab+ :comments org
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#+PROPERTY: header-args:matlab+ :results output
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#+PROPERTY: header-args:matlab+ :exports both
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#+PROPERTY: header-args:matlab+ :eval no-export
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#+PROPERTY: header-args:matlab+ :output-dir figs
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:END:
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* Measurement Description
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Random Signal is generated by one DAC of the SpeedGoat.
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The signal going out of the DAC is split into two:
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- one BNC cable is directly connected to one ADC of the SpeedGoat
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- one BNC cable goes two times in the Slip-Ring (from bottom to top and then from top to bottom) and then is connected to one ADC of the SpeedGoat
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Two measurements are done.
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| Data File | Description |
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|--------------------+-----------------------|
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| =mat/data_001.mat= | Slip-ring not turning |
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| =mat/data_002.mat= | Slip-ring turning |
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For each measurement, the measured signals are:
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| Data File | Description |
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|-----------+------------------------------------|
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| =t= | Time vector |
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| =x1= | Direct signal |
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| =x2= | Signal going through the Slip-Ring |
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The goal is to determine is the signal is altered when the spindle is rotating.
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Here, the rotation speed of the Slip-Ring is set to 1rpm.
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* Matlab Init :noexport:ignore:
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#+begin_src matlab :exports none :results silent :noweb yes
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<<matlab-init>>
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#+end_src
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* Load data
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We load the data of the z axis of two geophones.
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#+begin_src matlab :results none
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sr_off = load('mat/data_001.mat', 't', 'x1', 'x2');
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sr_on = load('mat/data_002.mat', 't', 'x1', 'x2');
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#+end_src
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* Analysis
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Let's first look at the signal produced by the DAC (figure [[fig:random_signal]]).
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#+begin_src matlab :results none
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figure;
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hold on;
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plot(sr_on.t, sr_on.x1);
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hold off;
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xlabel('Time [s]'); ylabel('Voltage [V]');
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xlim([0 10]);
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#+end_src
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#+NAME: fig:random_signal
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#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
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#+begin_src matlab :var filepath="figs/random_signal.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
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<<plt-matlab>>
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#+end_src
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#+NAME: fig:random_signal
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#+CAPTION: Random signal produced by the DAC
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#+RESULTS: fig:random_signal
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[[file:figs/random_signal.png]]
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We now look at the difference between the signal directly measured by the ADC and the signal that goes through the slip-ring (figure [[fig:slipring_comp_signals]]).
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#+begin_src matlab :results none
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figure;
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hold on;
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plot(sr_on.t, sr_on.x1 - sr_on.x2, 'DisplayName', 'Slip-Ring - $\omega = 1rpm$');
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plot(sr_off.t, sr_off.x1 - sr_off.x2,'DisplayName', 'Slip-Ring off');
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hold off;
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xlabel('Time [s]'); ylabel('Voltage [V]');
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xlim([0 10]);
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legend('Location', 'northeast');
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#+end_src
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#+NAME: fig:slipring_comp_signals
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#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
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#+begin_src matlab :var filepath="figs/slipring_comp_signals.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
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<<plt-matlab>>
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#+end_src
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#+NAME: fig:slipring_comp_signals
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#+CAPTION: Alteration of the signal when the slip-ring is turning
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#+RESULTS: fig:slipring_comp_signals
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[[file:figs/slipring_comp_signals.png]]
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* Conclusion
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#+begin_note
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*Remaining questions*:
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- Should the measurement be redone using voltage amplifiers?
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- Use higher rotation speed and measure for longer periods (to have multiple revolutions) ?
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#+end_note
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