diff --git a/Library/figs/.gitignore b/Library/figs/.gitignore new file mode 100644 index 0000000..366b623 --- /dev/null +++ b/Library/figs/.gitignore @@ -0,0 +1,3 @@ +*.svg +*.pdf +*.tex \ No newline at end of file diff --git a/Library/figs/slipring_asd.png b/Library/figs/slipring_asd.png new file mode 100644 index 0000000..7a00984 Binary files /dev/null and b/Library/figs/slipring_asd.png differ diff --git a/Library/figs/slipring_time.png b/Library/figs/slipring_time.png new file mode 100644 index 0000000..1412441 Binary files /dev/null and b/Library/figs/slipring_time.png differ diff --git a/Library/index.org b/Library/index.org new file mode 100644 index 0000000..5bb842a --- /dev/null +++ b/Library/index.org @@ -0,0 +1,299 @@ +#+TITLE:Measurements +:DRAWER: +#+STARTUP: overview + +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: + +#+PROPERTY: header-args:matlab :session *MATLAB* +#+PROPERTY: header-args:matlab+ :comments org +#+PROPERTY: header-args:matlab+ :results output +#+PROPERTY: header-args:matlab+ :exports both +#+PROPERTY: header-args:matlab+ :eval no-export +#+PROPERTY: header-args:matlab+ :output-dir figs +:END: + +For all the measurements here, the geophones are L22. +The signals are amplified with voltage amplifiers with a gain of 60dB. +The voltage amplifiers include a low pass filter with a cut-off frequency at 1kHz. + +* Effect of the control system of each stage + +** Experimental Setup +One geophone is on the marble, the other at the sample location (see figures below). + +The signal from the top geophone goes through the slip-ring. + +The signals from the geophones are amplified by a voltage amplifier with a gain of 60dB. +The voltage amplifier also include a low pass filter with a corner frequency of 1kHz. + +#+name: fig:setup_ty_1 +#+caption: Figure caption +#+attr_html: :width 500px +[[file:./img/IMG_20190430_112613.jpg]] + +#+name: fig:setup_ty_2 +#+caption: Figure caption +#+attr_html: :width 500px +[[file:./img/IMG_20190430_112615.jpg]] + +#+name: fig:setup_ty_3 +#+caption: Figure caption +#+attr_html: :width 500px +[[file:./img/IMG_20190430_112620.jpg]] + +Two measurements are done: +| Setup | Data File | +|----------------------+--------------------| +| Control of Ty is on | =mat/data_001.mat= | +| Control of Ty is off | =mat/data_002.mat= | + +For each of the measurements +| Variable | Description | +|----------+--------------------------------------------------------------------| +| =t= | Time Vector | +| =x1= | Voltage measured across the geophone placed on the marble | +| =x2= | Voltage measured across the geophone placed at the sample location | + +Measurements are 50s long. + +** Matlab Init :noexport:ignore: +#+begin_src matlab :exports none :results silent :noweb yes + <> +#+end_src + +** Load data +We load the data of the z axis of two geophones. +#+begin_src matlab :results none + tyOn = load('mat/data_001.mat', 't', 'x1', 'x2'); + tyOff = load('mat/data_002.mat', 't', 'x1', 'x2'); +#+end_src + +** Analysis +#+begin_src matlab :results none + dt = tyOn.t(2)-tyOn.t(1); + Fs = 1/dt; +#+end_src + +#+begin_src matlab :results none + figure; + hold on; + plot(tyOn.t, tyOn.x1); + plot(tyOn.t, tyOn.x2); + hold off; + legend({'x1 - ON', 'x2 - ON'}); +#+end_src + +#+begin_src matlab :results none + figure; + hold on; + plot(tyOff.t, tyOff.x1); + plot(tyOff.t, tyOff.x2); + hold off; + legend({'x1 - OFF', 'x2 - OFF'}); +#+end_src + +#+begin_src matlab :results none + Fs = 1/dt; + win = hanning(ceil(10*Fs)); +#+end_src + +#+begin_src matlab :results none + [pxOn1, f] = pwelch(tyOn.x1, win, [], [], Fs); + [pxOn2, ~] = pwelch(tyOn.x2, win, [], [], Fs); + + [pxOff1, ~] = pwelch(tyOff.x1, win, [], [], Fs); + [pxOff2, ~] = pwelch(tyOff.x2, win, [], [], Fs); +#+end_src + +#+begin_src matlab :results none + figure; + hold on; + plot(f, sqrt(pxOn1)); + plot(f, sqrt(pxOn2)); + hold off; + set(gca, 'xscale', 'log'); + set(gca, 'yscale', 'log'); + xlabel('Frequency [Hz]'); ylabel('PSD [m/s/sqrt(Hz)]') + % xlim([2, 500]); +#+end_src + +#+begin_src matlab :results none + figure; + hold on; + plot(f, sqrt(pxOn1)); + plot(f, sqrt(pxOff1)); + hold off; + set(gca, 'xscale', 'log'); + set(gca, 'yscale', 'log'); + xlabel('Frequency [Hz]'); ylabel('PSD [m/s/sqrt(Hz)]') + % xlim([2, 500]); +#+end_src + +#+begin_src matlab :results none + figure; + hold on; + plot(f, sqrt(pxOn2)); + plot(f, sqrt(pxOff2)); + hold off; + set(gca, 'xscale', 'log'); + set(gca, 'yscale', 'log'); + xlabel('Frequency [Hz]'); ylabel('PSD [m/s/sqrt(Hz)]') + % xlim([2, 500]); +#+end_src + +#+begin_src matlab :results none + [T_off, ~] = tfestimate(tyOff.x1, tyOff.x2, win, [], [], Fs); + [coh_off, ~] = mscohere(tyOff.x1, tyOff.x2, win, [], [], Fs); + + [T_on, ~] = tfestimate(tyOn.x1, tyOn.x2, win, [], [], Fs); + [coh_on, ~] = mscohere(tyOn.x1, tyOn.x2, win, [], [], Fs); +#+end_src + +#+begin_src matlab :results none :exports none + figure; + hold on; + plot(f, coh_on); + plot(f, coh_off); + hold off; + set(gca, 'xscale', 'log'); + xlabel('Frequency [Hz]'); ylabel('Coherence'); + ylim([0,1]); xlim([1, 500]); +#+end_src + +#+begin_src matlab :results none :exports none + figure; + ax1 = subplot(2, 1, 1); + hold on; + plot(f, abs(T_on)); + plot(f, abs(T_off)); + hold off; + set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); + set(gca, 'XTickLabel',[]); + ylabel('Magnitude'); + + ax2 = subplot(2, 1, 2); + hold on; + plot(f, mod(180+180/pi*phase(T_on), 360)-180); + plot(f, mod(180+180/pi*phase(T_off), 360)-180); + hold off; + set(gca, 'xscale', 'log'); + ylim([-180, 180]); + yticks([-180, -90, 0, 90, 180]); + xlabel('Frequency [Hz]'); ylabel('Phase'); + + linkaxes([ax1,ax2],'x'); + xlim([1, 500]); +#+end_src +* Effect of the Slip-Ring on the signal +** Experimental Setup +Two measurements are made where the control of all the stages are OFF. + +One geophone is located on the marble while the other is located at the sample location. + +The two measurements are: +| Measurement File | Description | +|------------------+------------------------------------------------------------------| +| =meas_008.mat= | Signal from the top geophone does not goes through the Slip-ring | +| =meas_009.mat= | Signal goes through the Slip-ring | + +Each of the measurement =mat= file contains one =data= array with 3 columns: +| Column number | Description | +|---------------+-------------------| +| 1 | Geophone - Marble | +| 2 | Geophone - Sample | +| 3 | Time | + +** Matlab Init :noexport:ignore: +#+begin_src matlab :exports none :results silent :noweb yes + <> +#+end_src + +** Load data +We load the data of the z axis of two geophones. +#+begin_src matlab :results none + data8 = load('mat/data_008.mat', 'data'); + data9 = load('mat/data_009.mat', 'data'); +#+end_src + +** Analysis - Time Domain +#+begin_src matlab :results none + figure; + hold on; + plot(data9.data(:, 3), data9.data(:, 2), 'DisplayName', 'Slip-Ring'); + plot(data8.data(:, 3), data8.data(:, 2), 'DisplayName', 'Wire'); + hold off; + xlabel('Time [s]'); ylabel('Voltage [V]'); + xlim([0, 50]); + legend(); +#+end_src + +#+NAME: fig:slipring_time +#+HEADER: :tangle no :exports results :results value raw replace :noweb yes +#+begin_src matlab :var filepath="figs/slipring_time.pdf" :var figsize="wide-tall" :post pdf2svg(file=*this*, ext="png") + <> +#+end_src + +#+NAME: fig:slipring_time +#+CAPTION: Effect of the Slip-Ring on the measured signal - Time domain +#+RESULTS: fig:slipring_time +[[file:figs/slipring_time.png]] + +** Analysis - Frequency Domain +#+begin_src matlab :results none + dt = data8.data(2, 3) - data8.data(1, 3); + + Fs = 1/dt; + win = hanning(ceil(1*Fs)); +#+end_src + +#+begin_src matlab :results none + [pxx8, f] = pwelch(data8.data(:, 2), win, [], [], Fs); + [pxx9, ~] = pwelch(data9.data(:, 2), win, [], [], Fs); +#+end_src + +#+begin_src matlab :results none + figure; + hold on; + plot(f, sqrt(pxx9), 'DisplayName', 'Slip-Ring'); + plot(f, sqrt(pxx8), 'DisplayName', 'Wire'); + hold off; + set(gca, 'xscale', 'log'); + set(gca, 'yscale', 'log'); + xlabel('Frequency [Hz]'); ylabel('ASD [V/sqrt(Hz)]') + xlim([1, 500]); + legend('Location', 'southwest'); +#+end_src + +#+NAME: fig:slipring_asd +#+HEADER: :tangle no :exports results :results value raw replace :noweb yes +#+begin_src matlab :var filepath="figs/slipring_asd.pdf" :var figsize="wide-tall" :post pdf2svg(file=*this*, ext="png") + <> +#+end_src + +#+NAME: fig:slipring_asd +#+CAPTION: Effect of the Slip-Ring on the measured signal - Frequency domain +#+RESULTS: fig:slipring_asd +[[file:figs/slipring_asd.png]] + +** Conclusion +*Remaining questions to answer*: +- Why is there a sharp peak at 300Hz? +- Why the use of the Slip-Ring does induce a noise? +- Can the capacitive/inductive properties of the wires in the Slip-ring does not play well with the geophone? (resonant RLC circuit) + +* Measurement when signal from top geophone does not go trought the slip-ring + +| Ty | Ry | Slip Ring | Spindle | Hexapod | Meas. file | +|------+------+-----------+---------+---------+----------------| +| *ON* | *ON* | *ON* | *ON* | *ON* | =meas_003.mat= | +| OFF | *ON* | *ON* | *ON* | *ON* | =meas_004.mat= | +| OFF | OFF | *ON* | *ON* | *ON* | =meas_005.mat= | +| OFF | OFF | OFF | *ON* | *ON* | =meas_006.mat= | +| OFF | OFF | OFF | OFF | *ON* | =meas_007.mat= | +| OFF | OFF | OFF | OFF | OFF | =meas_008.mat= |