%% Clear Workspace and Close figures clear; close all; clc; %% Intialize Laplace variable s = zpk('s'); % Importation of the data % First, load all the measurement files: meas = {}; meas{1} = load('./mat/Measurement1.mat'); meas{2} = load('./mat/Measurement2.mat'); meas{3} = load('./mat/Measurement3.mat'); meas{4} = load('./mat/Measurement4.mat'); meas{5} = load('./mat/Measurement5.mat'); % Change the track name for measurements 3 and 4. meas{3}.Track1_Name = 'Input 1: Hexa Z'; meas{4}.Track1_Name = 'Input 1: Hexa Z'; % Variables for analysis % We define the sampling frequency and the time vectors for the plots. Fs = 256; % [Hz] dt = 1/(Fs); t1 = dt*(0:length(meas{1}.Track1)-1); t2 = dt*(0:length(meas{2}.Track1)-1); t3 = dt*(0:length(meas{3}.Track1)-1); t4 = dt*(0:length(meas{4}.Track1)-1); t5 = dt*(0:length(meas{5}.Track1)-1); % For the frequency analysis, we define the frequency limits for the plot. fmin = 1; % [Hz] fmax = 100; % [Hz] % Then we define the windows that will be used to average the results. psd_window = hanning(2*fmin/dt); % Coherence between the two vertical geophones on the Tilt Stage % We first compute the coherence between the two geophones located on the tilt stage. The result is shown on figure [[fig:coherence_vertical_tilt_sensors]]. [coh, f] = mscohere(meas{1}.Track1(:), meas{1}.Track2(:), psd_window, [], [], Fs); figure; plot(f, coh); set(gca, 'xscale', 'log'); ylim([0, 1]); xlabel('Frequency [Hz]'); ylabel('Coherence'); % #+NAME: fig:coherence_vertical_tilt_sensors % #+CAPTION: Coherence between the two vertical sensors positionned on the Tilt Stage % #+RESULTS: fig:coherence_vertical_tilt_sensors % [[file:figs/coherence_vertical_tilt_sensors.png]] % We then compute the transfer function from one sensor to the other (figure [[fig:tf_vertical_tilt_sensors]]). [tf23, f] = tfestimate(meas{1}.Track1(:), meas{1}.Track2(:), psd_window, [], [], Fs); figure; ax1 = subplot(2,1,1); plot(f, abs(tf23)); set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); set(gca, 'XTickLabel',[]); ylabel('Magnitude [V/(m/s)]'); ax2 = subplot(2,1,2); plot(f, 180/pi*angle(tf23)); set(gca,'xscale','log'); yticks(-180:90:180); ylim([-180 180]); xlabel('Frequency [Hz]'); ylabel('Phase [deg]'); linkaxes([ax1,ax2],'x'); % Data Post Processing % When using two geophone sensors on the same tilt stage (measurements 1 and 2), we post-process the data to obtain the z displacement and the rotation of the tilt stage: meas1_z = (meas{1}.Track1+meas{1}.Track2)/2; meas1_tilt = (meas{1}.Track1-meas{1}.Track2)/2; meas{1}.Track1 = meas1_z; meas{1}.Track1_Y_Magnitude = 'Meter / second'; meas{1}.Track1_Name = 'Ry Z'; meas{1}.Track2 = meas1_tilt; meas{1}.Track2_Y_Magnitude = 'Rad / second'; meas{1}.Track2_Name = 'Ry Tilt'; meas2_z = (meas{2}.Track1+meas{2}.Track2)/2; meas2_tilt = (meas{2}.Track1-meas{2}.Track2)/2; meas{2}.Track1 = meas2_z; meas{2}.Track1_Y_Magnitude = 'Meter / second'; meas{2}.Track1_Name = 'Ry Z'; meas{2}.Track2 = meas2_tilt; meas{2}.Track2_Y_Magnitude = 'Rad / second'; meas{2}.Track2_Name = 'Ry Tilt'; % Normalization % Parameters of the geophone are defined below. % The transfer function from geophone velocity to measured voltage is shown on figure [[fig:L4C_bode_plot]]. % Measurements will be normalized by the inverse of this transfer function in order to go from voltage measurement to velocity measurement. L4C_w0 = 2*pi; % [rad/s] L4C_ksi = 0.28; L4C_G0 = 276.8; % [V/(m/s)] L4C_G = L4C_G0*(s/L4C_w0)^2/((s/L4C_w0)^2 + 2*L4C_ksi*(s/L4C_w0) + 1); freqs = logspace(-2, 2, 1000); figure; ax1 = subplot(2,1,1); plot(freqs, abs(squeeze(freqresp(L4C_G, freqs, 'Hz')))); set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); set(gca, 'XTickLabel',[]); ylabel('Magnitude [V/(m/s)]'); ax2 = subplot(2,1,2); plot(freqs, 180/pi*angle(squeeze(freqresp(L4C_G, freqs, 'Hz')))); set(gca,'xscale','log'); yticks(-180:90:180); ylim([-180 180]); xlabel('Frequency [Hz]'); ylabel('Phase [deg]'); linkaxes([ax1,ax2],'x'); % #+NAME: fig:L4C_bode_plot % #+CAPTION: Bode plot of the L4C Geophone % #+RESULTS: fig:L4C_bode_plot % [[file:figs/L4C_bode_plot.png]] meas{1}.Track1 = (meas{1}.Track1)./276.8; meas{1}.Track2 = (meas{1}.Track2)./276.8; meas{1}.Track3 = (meas{1}.Track3)./276.8; meas{2}.Track1 = (meas{2}.Track1)./276.8; meas{2}.Track2 = (meas{2}.Track2)./276.8; meas{2}.Track3 = (meas{2}.Track3)./276.8; meas{3}.Track1 = (meas{3}.Track1)./276.8; meas{3}.Track2 = (meas{3}.Track2)./276.8; meas{3}.Track3 = (meas{3}.Track3)./276.8; meas{4}.Track1 = (meas{4}.Track1)./276.8; meas{4}.Track2 = (meas{4}.Track2)./276.8; meas{4}.Track3 = (meas{4}.Track3)./276.8; meas{5}.Track1 = (meas{5}.Track1)./276.8; meas{5}.Track2 = (meas{5}.Track2)./276.8; meas{5}.Track3 = (meas{5}.Track3)./276.8; meas{5}.Track4 = (meas{5}.Track4)./276.8; meas{1}.Track1_norm = lsim(inv(L4C_G), meas{1}.Track1, t1); meas{1}.Track2_norm = lsim(inv(L4C_G), meas{1}.Track2, t1); meas{1}.Track3_norm = lsim(inv(L4C_G), meas{1}.Track3, t1); meas{2}.Track1_norm = lsim(inv(L4C_G), meas{2}.Track1, t2); meas{2}.Track2_norm = lsim(inv(L4C_G), meas{2}.Track2, t2); meas{2}.Track3_norm = lsim(inv(L4C_G), meas{2}.Track3, t2); meas{3}.Track1_norm = lsim(inv(L4C_G), meas{3}.Track1, t3); meas{3}.Track2_norm = lsim(inv(L4C_G), meas{3}.Track2, t3); meas{3}.Track3_norm = lsim(inv(L4C_G), meas{3}.Track3, t3); meas{4}.Track1_norm = lsim(inv(L4C_G), meas{4}.Track1, t4); meas{4}.Track2_norm = lsim(inv(L4C_G), meas{4}.Track2, t4); meas{4}.Track3_norm = lsim(inv(L4C_G), meas{4}.Track3, t4); meas{5}.Track1_norm = lsim(inv(L4C_G), meas{5}.Track1, t5); meas{5}.Track2_norm = lsim(inv(L4C_G), meas{5}.Track2, t5); meas{5}.Track3_norm = lsim(inv(L4C_G), meas{5}.Track3, t5); meas{5}.Track4_norm = lsim(inv(L4C_G), meas{5}.Track4, t5); % Measurement 1 - Effect of Ty stage % The configuration for this measurement is shown table [[tab:conf_meas1]]. % #+CAPTION: Stages configuration - Measurement 1 % #+NAME: tab:conf_meas1 % | Time | 0-309 | 309-end | % |----------+-------+---------| % | Ty | OFF | *ON* | % | Ry | OFF | OFF | % | SlipRing | OFF | OFF | % | Spindle | OFF | OFF | % | Hexa | OFF | OFF | % We then plot the measurements in time domain (figure [[fig:meas1]]). % #+begin_important % We observe strange behavior when the Ty stage is turned on. % How can we explain that? % #+end_important figure; hold on; plot(t1(ceil(300/dt):ceil(340/dt)), meas{1}.Track1(ceil(300/dt):ceil(340/dt))); plot(t1(ceil(300/dt):ceil(340/dt)), meas{1}.Track2(ceil(300/dt):ceil(340/dt))); plot(t1(ceil(300/dt):ceil(340/dt)), meas{1}.Track3(ceil(300/dt):ceil(340/dt))); hold off; xlabel('Time [s]'); ylabel('Velocity [m/s]'); legend({meas{1}.Track1_Name, meas{1}.Track2_Name, meas{1}.Track3_Name}, 'Location', 'northeast') % #+LABEL: fig:meas1 % #+CAPTION: Time domain - measurement 1 % #+RESULTS: fig:meas1 % [[file:figs/meas1.png]] % To understand what is going on, instead of looking at the velocity, we can look at the displacement by integrating the data. The displacement is computed by integrating the velocity using =cumtrapz= function. % Then we plot the position with respect to time (figure [[fig:meas1_disp]]). figure; hold on; plot(t1, cumtrapz(t1, meas{1}.Track3)); hold off; xlim([300, 340]); xlabel('Time [s]'); ylabel('Displacement [m]'); % #+LABEL: fig:meas1_disp % #+CAPTION: Y displacement of the Ty stage % #+RESULTS: fig:meas1_disp % [[file:figs/meas1_disp.png]] % We when compute the power spectral density of each measurement before and after turning on the stage. [pxx111, f11] = pwelch(meas{1}.Track1(1:ceil(300/dt)), psd_window, [], [], Fs); [pxx112, f12] = pwelch(meas{1}.Track1(ceil(350/dt):end), psd_window, [], [], Fs); [pxx121, ~] = pwelch(meas{1}.Track2(1:ceil(300/dt)), psd_window, [], [], Fs); [pxx122, ~] = pwelch(meas{1}.Track2(ceil(350/dt):end), psd_window, [], [], Fs); [pxx131, ~] = pwelch(meas{1}.Track3(1:ceil(300/dt)), psd_window, [], [], Fs); [pxx132, ~] = pwelch(meas{1}.Track3(ceil(350/dt):end), psd_window, [], [], Fs); % We finally plot the power spectral density of each track (figures [[fig:meas1_ry_z_psd]], [[fig:meas1_ry_tilt_psd]], [[fig:meas1_ty_y_psd]]). figure; hold on; plot(f11, sqrt(pxx111)./abs(squeeze(freqresp(L4C_G, f11, 'Hz')))); plot(f12, sqrt(pxx112)./abs(squeeze(freqresp(L4C_G, f12, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{1}.Track1_Name)); legend({'0-300', '350-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas1_ry_z_psd % #+CAPTION: PSD of the Z velocity of Ry stage - measurement 1 % #+RESULTS: fig:meas1_ry_z_psd % [[file:figs/meas1_ry_z_psd.png]] figure; hold on; plot(f11, sqrt(pxx121)./abs(squeeze(freqresp(L4C_G, f11, 'Hz')))); plot(f12, sqrt(pxx122)./abs(squeeze(freqresp(L4C_G, f12, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$rad/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{1}.Track2_Name)); legend({'0-300', '350-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas1_ry_tilt_psd % #+CAPTION: PSD of the Rotation of Ry Stage - measurement 1 % #+RESULTS: fig:meas1_ry_tilt_psd % [[file:figs/meas1_ry_tilt_psd.png]] figure; hold on; plot(f11, sqrt(pxx131)./abs(squeeze(freqresp(L4C_G, f11, 'Hz')))); plot(f12, sqrt(pxx132)./abs(squeeze(freqresp(L4C_G, f12, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{1}.Track3_Name)); legend({'0-300', '350-end'}, 'Location', 'southwest'); hold off; % Measurement 2 - Effect of Ry stage % The tilt stage is turned ON at around 326 seconds (table [[tab:conf_meas2]]). % #+CAPTION: Stages configuration - Measurement 2 % #+NAME: tab:conf_meas2 % | Time | 0-326 | 326-end | % |----------+-------+---------| % | Ty | OFF | OFF | % | Ry | OFF | *ON* | % | SlipRing | OFF | OFF | % | Spindle | OFF | OFF | % | Hexa | OFF | OFF | % We plot the time domain (figure [[fig:meas2]]) and we don't observe anything special in the time domain. figure; hold on; plot(t2(ceil(300/dt):ceil(350/dt)), meas{2}.Track1(ceil(300/dt):ceil(350/dt))); plot(t2(ceil(300/dt):ceil(350/dt)), meas{2}.Track3(ceil(300/dt):ceil(350/dt))); plot(t2(ceil(300/dt):ceil(350/dt)), meas{2}.Track2(ceil(300/dt):ceil(350/dt))); hold off; xlabel('Time [s]'); ylabel('Velocity [m/s]'); legend({meas{2}.Track1_Name, meas{2}.Track2_Name, meas{2}.Track3_Name}, 'Location', 'northeast') xlim([300, 350]); % #+LABEL: fig:meas2 % #+CAPTION: Time domain - measurement 2 % #+RESULTS: fig:meas2 % [[file:figs/meas2.png]] figure; hold on; plot(t2, cumtrapz(t2, meas{2}.Track1)); plot(t2, cumtrapz(t2, meas{2}.Track2)); plot(t2, cumtrapz(t2, meas{2}.Track3)); hold off; xlim([300, 350]); xlabel('Time [s]'); ylabel('Displacement [m]'); legend({meas{2}.Track1_Name, meas{2}.Track2_Name, meas{2}.Track3_Name}, 'Location', 'northeast') % #+LABEL: fig:meas2_disp % #+CAPTION: Time domain - measurement 2 % #+RESULTS: fig:meas2_disp % [[file:figs/meas2_disp.png]] % We compute the PSD of each track and we plot them (figures [[fig:meas2_ry_z_psd]], [[fig:meas2_ry_tilt_psd]] and [[fig:meas2_ty_y_psd]] ). [pxx211, f21] = pwelch(meas{2}.Track1(1:ceil(326/dt)), psd_window, [], [], Fs); [pxx212, f22] = pwelch(meas{2}.Track1(ceil(326/dt):end), psd_window, [], [], Fs); [pxx221, ~] = pwelch(meas{2}.Track2(1:ceil(326/dt)), psd_window, [], [], Fs); [pxx222, ~] = pwelch(meas{2}.Track2(ceil(326/dt):end), psd_window, [], [], Fs); [pxx231, ~] = pwelch(meas{2}.Track3(1:ceil(326/dt)), psd_window, [], [], Fs); [pxx232, ~] = pwelch(meas{2}.Track3(ceil(326/dt):end), psd_window, [], [], Fs); figure; hold on; plot(f21, sqrt(pxx211)./abs(squeeze(freqresp(L4C_G, f21, 'Hz')))); plot(f22, sqrt(pxx212)./abs(squeeze(freqresp(L4C_G, f22, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{2}.Track1_Name)); legend({'0-326', '326-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas2_ry_z_psd % #+CAPTION: PSD of the Z velocity of Ry Stage - measurement 2 % #+RESULTS: fig:meas2_ry_z_psd % [[file:figs/meas2_ry_z_psd.png]] figure; hold on; plot(f21, sqrt(pxx221)./abs(squeeze(freqresp(L4C_G, f21, 'Hz')))); plot(f22, sqrt(pxx222)./abs(squeeze(freqresp(L4C_G, f22, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$rad/s/\sqrt(Hz)$]'); title(sprintf('%s', meas{2}.Track2_Name)); legend({'0-326', '326-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas2_ry_tilt_psd % #+CAPTION: PSD of the Rotation motion of Ry Stage - measurement 2 % #+RESULTS: fig:meas2_ry_tilt_psd % [[file:figs/meas2_ry_tilt_psd.png]] figure; hold on; plot(f21, sqrt(pxx231)./abs(squeeze(freqresp(L4C_G, f21, 'Hz')))); plot(f22, sqrt(pxx232)./abs(squeeze(freqresp(L4C_G, f22, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{2}.Track3_Name)); legend({'0-326', '326-end'}, 'Location', 'southwest'); hold off; % Measurement 3 - Effect of the Hexapod % The hexapod is turned off after 406 seconds (table [[tab:conf_meas3]]). % #+CAPTION: Stages configuration - Measurement 3 % #+NAME: tab:conf_meas3 % | Time | 0-406 | 406-end | % |----------+-------+---------| % | Ty | OFF | OFF | % | Ry | *ON* | *ON* | % | SlipRing | OFF | OFF | % | Spindle | OFF | OFF | % | Hexa | *ON* | OFF | % The time domain result is shown figure [[fig:meas3]]. figure; hold on; plot(t3(ceil(380/dt):ceil(420/dt)), meas{3}.Track1(ceil(380/dt):ceil(420/dt))); plot(t3(ceil(380/dt):ceil(420/dt)), meas{3}.Track2(ceil(380/dt):ceil(420/dt))); plot(t3(ceil(380/dt):ceil(420/dt)), meas{3}.Track3(ceil(380/dt):ceil(420/dt))); hold off; xlabel('Time [s]'); ylabel('Velocity [m/s]'); legend({meas{3}.Track1_Name, meas{3}.Track2_Name, meas{3}.Track3_Name}, 'Location', 'northeast') % #+LABEL: fig:meas3 % #+CAPTION: Time domain - measurement 3 % #+RESULTS: fig:meas3 % [[file:figs/meas3.png]] figure; hold on; plot(t3, cumtrapz(t3, meas{3}.Track1)); plot(t3, cumtrapz(t3, meas{3}.Track2)); plot(t3, cumtrapz(t3, meas{3}.Track3)); hold off; xlim([350, 450]); xlabel('Time [s]'); ylabel('Displacement [m]'); legend({meas{3}.Track1_Name, meas{3}.Track2_Name, meas{3}.Track3_Name}, 'Location', 'northeast') % #+LABEL: fig:meas3_disp % #+CAPTION: Time domain - measurement 3 % #+RESULTS: fig:meas3_disp % [[file:figs/meas3_disp.png]] % We then compute the PSD of each track before and after turning off the hexapod and plot the results in the figures [[fig:meas3_hexa_z_psd]], [[fig:meas3_ry_z_psd]] and [[fig:meas3_ty_y_psd]]. [pxx311, f31] = pwelch(meas{3}.Track1(1:ceil(400/dt)), psd_window, [], [], Fs); [pxx312, f32] = pwelch(meas{3}.Track1(ceil(420/dt):end), psd_window, [], [], Fs); [pxx321, ~] = pwelch(meas{3}.Track2(1:ceil(400/dt)), psd_window, [], [], Fs); [pxx322, ~] = pwelch(meas{3}.Track2(ceil(420/dt):end), psd_window, [], [], Fs); [pxx331, ~] = pwelch(meas{3}.Track3(1:ceil(400/dt)), psd_window, [], [], Fs); [pxx332, ~] = pwelch(meas{3}.Track3(ceil(420/dt):end), psd_window, [], [], Fs); figure; hold on; plot(f31, sqrt(pxx311)./abs(squeeze(freqresp(L4C_G, f31, 'Hz')))); plot(f32, sqrt(pxx312)./abs(squeeze(freqresp(L4C_G, f32, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{3}.Track1_Name)); legend({'0-400', '420-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas3_hexa_z_psd % #+CAPTION: PSD of the Z velocity of the Hexapod - measurement 3 % #+RESULTS: fig:meas3_hexa_z_psd % [[file:figs/meas3_hexa_z_psd.png]] figure; hold on; plot(f31, sqrt(pxx321)./abs(squeeze(freqresp(L4C_G, f31, 'Hz')))); plot(f32, sqrt(pxx322)./abs(squeeze(freqresp(L4C_G, f32, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{3}.Track2_Name)); legend({'0-400', '420-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas3_ry_z_psd % #+CAPTION: PSD of the Z velocity of the Ry stage - measurement 3 % #+RESULTS: fig:meas3_ry_z_psd % [[file:figs/meas3_ry_z_psd.png]] figure; hold on; plot(f31, sqrt(pxx331)./abs(squeeze(freqresp(L4C_G, f31, 'Hz')))); plot(f32, sqrt(pxx332)./abs(squeeze(freqresp(L4C_G, f32, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{3}.Track3_Name)); legend({'0-400', '420-end'}, 'Location', 'southwest'); hold off; % Measurement 4 - Effect of the Splip-Ring and Spindle % The slip ring is turned on at 300s, then the spindle is turned on at 620s (table [[tab:conf_meas4]]). The time domain signals are shown figure [[fig:meas4]]. % #+CAPTION: Stages configuration - Measurement 4 % #+NAME: tab:conf_meas4 % | Time | 0-300 | 300-620 | 620-end | % |----------+-------+---------+---------| % | Ty | OFF | OFF | OFF | % | Ry | OFF | OFF | OFF | % | SlipRing | OFF | *ON* | *ON* | % | Spindle | OFF | OFF | *ON* | % | Hexa | OFF | OFF | OFF | figure; hold on; plot(t4, meas{4}.Track1); plot(t4, meas{4}.Track2); plot(t4, meas{4}.Track3); hold off; xlim([t4(1), t4(end)]); xlabel('Time [s]'); ylabel('Velocity [m/s]'); legend({meas{4}.Track1_Name, meas{4}.Track2_Name, meas{4}.Track3_Name}, 'Location', 'southwest') % #+LABEL: fig:meas4 % #+CAPTION: Time domain - measurement 4 % #+RESULTS: fig:meas4 % [[file:figs/meas4.png]] figure; subplot(1, 2, 1); hold on; plot(t4, cumtrapz(t4, meas{4}.Track1)); plot(t4, cumtrapz(t4, meas{4}.Track2)); plot(t4, cumtrapz(t4, meas{4}.Track3)); hold off; xlim([250, 350]); xlabel('Time [s]'); ylabel('Displacement [m]'); legend({meas{4}.Track1_Name, meas{4}.Track2_Name, meas{4}.Track3_Name}, 'Location', 'northwest') subplot(1, 2, 2); hold on; plot(t4, cumtrapz(t4, meas{4}.Track1)); plot(t4, cumtrapz(t4, meas{4}.Track2)); plot(t4, cumtrapz(t4, meas{4}.Track3)); hold off; xlim([600, 650]); xlabel('Time [s]'); ylabel('Displacement [m]'); % #+LABEL: fig:meas4_int % #+CAPTION: Time domain - measurement 4 % #+RESULTS: fig:meas4_int % [[file:figs/meas4_int.png]] % The PSD of each track are computed using the code below. [pxx411, f41] = pwelch(meas{4}.Track1(1:ceil(280/dt)), psd_window, [], [], Fs); [pxx412, f42] = pwelch(meas{4}.Track1(ceil(280/dt):ceil(600/dt)), psd_window, [], [], Fs); [pxx413, f43] = pwelch(meas{4}.Track1(ceil(640/dt):end), psd_window, [], [], Fs); [pxx421, ~] = pwelch(meas{4}.Track2(1:ceil(280/dt)), psd_window, [], [], Fs); [pxx422, ~] = pwelch(meas{4}.Track2(ceil(280/dt):ceil(600/dt)), psd_window, [], [], Fs); [pxx423, ~] = pwelch(meas{4}.Track2(ceil(640/dt):end), psd_window, [], [], Fs); [pxx431, ~] = pwelch(meas{4}.Track3(1:ceil(280/dt)), psd_window, [], [], Fs); [pxx432, ~] = pwelch(meas{4}.Track3(ceil(280/dt):ceil(600/dt)), psd_window, [], [], Fs); [pxx433, ~] = pwelch(meas{4}.Track3(ceil(640/dt):end), psd_window, [], [], Fs); f41 = f41(2:end); f42 = f42(2:end); f43 = f43(2:end); pxx411 = pxx411(2:end); pxx412 = pxx412(2:end); pxx413 = pxx413(2:end); pxx421 = pxx421(2:end); pxx422 = pxx422(2:end); pxx423 = pxx423(2:end); pxx431 = pxx431(2:end); pxx432 = pxx432(2:end); pxx433 = pxx433(2:end); figure; hold on; plot(f41, sqrt(pxx411)./abs(squeeze(freqresp(L4C_G, f41, 'Hz')))); plot(f42, sqrt(pxx412)./abs(squeeze(freqresp(L4C_G, f42, 'Hz')))); plot(f43, sqrt(pxx413)./abs(squeeze(freqresp(L4C_G, f43, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{4}.Track1_Name)); legend({'0-280', '320-600', '640-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas4_hexa_z_psd % #+CAPTION: PSD of the Z velocity of the Hexapod - measurement 4 % #+RESULTS: fig:meas4_hexa_z_psd % [[file:figs/meas4_hexa_z_psd.png]] % We plot the PSD of the displacement. figure; hold on; plot(f41, sqrt(pxx411)./abs(squeeze(freqresp(L4C_G, f41, 'Hz')))./(2*pi*f41)); plot(f42, sqrt(pxx412)./abs(squeeze(freqresp(L4C_G, f42, 'Hz')))./(2*pi*f42)); plot(f43, sqrt(pxx413)./abs(squeeze(freqresp(L4C_G, f43, 'Hz')))./(2*pi*f43)); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/\sqrt{Hz}$]'); title(sprintf('%s', meas{4}.Track1_Name)); legend({'0-280', '320-600', '640-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas4_hexa_z_psd_int % #+CAPTION: PSD_INT of the Z velocity of the Hexapod - measurement 4 % #+RESULTS: fig:meas4_hexa_z_psd_int % [[file:figs/meas4_hexa_z_psd_int.png]] % And we compute the Cumulative amplitude spectrum. figure; hold on; plot(f41, sqrt(cumsum(pxx431./abs(squeeze(freqresp(L4C_G, f41, 'Hz'))).^2./(2*pi*f41).*(f41 - [0; f41(1:end-1)])))); plot(f42, sqrt(cumsum(pxx432./abs(squeeze(freqresp(L4C_G, f42, 'Hz'))).^2./(2*pi*f42).*(f42 - [0; f42(1:end-1)])))); plot(f43, sqrt(cumsum(pxx433./abs(squeeze(freqresp(L4C_G, f43, 'Hz'))).^2./(2*pi*f43).*(f43 - [0; f43(1:end-1)])))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('CAS [$m$ rms]'); title(sprintf('%s', meas{4}.Track1_Name)); legend({'0-280', '320-600', '640-end'}, 'Location', 'southwest'); hold off; figure; hold on; plot(f41, sqrt(pxx421)./abs(squeeze(freqresp(L4C_G, f41, 'Hz')))); plot(f42, sqrt(pxx422)./abs(squeeze(freqresp(L4C_G, f42, 'Hz')))); plot(f43, sqrt(pxx423)./abs(squeeze(freqresp(L4C_G, f43, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{4}.Track2_Name)); legend({'0-280', '320-600', '640-end'}, 'Location', 'southwest'); hold off; % #+LABEL: fig:meas4_ry_z_psd % #+CAPTION: PSD of the Ry rotation in the Y direction - measurement 4 % #+RESULTS: fig:meas4_ry_z_psd % [[file:figs/meas4_ry_z_psd.png]] figure; hold on; plot(f41, sqrt(pxx431)./abs(squeeze(freqresp(L4C_G, f41, 'Hz')))); plot(f42, sqrt(pxx432)./abs(squeeze(freqresp(L4C_G, f42, 'Hz')))); plot(f43, sqrt(pxx433)./abs(squeeze(freqresp(L4C_G, f43, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); title(sprintf('%s', meas{4}.Track3_Name)); legend({'0-280', '320-600', '640-end'}, 'Location', 'southwest'); hold off; % Measurement 5 - Transmission from ground to marble % This measurement just consists of measurement of Y-Z motion of the ground and the marble. % The time domain signals are shown on figure [[fig:meas5]]. figure; hold on; plot(t5, meas{5}.Track1); plot(t5, meas{5}.Track2); plot(t5, meas{5}.Track3); plot(t5, meas{5}.Track4); hold off; xlabel('Time [s]'); ylabel('Velocity [m/s]'); legend({meas{5}.Track1_Name, meas{5}.Track2_Name, meas{5}.Track3_Name, meas{5}.Track4_Name}, 'Location', 'northeast') % #+LABEL: fig:meas5 % #+CAPTION: Time domain - measurement 5 % #+RESULTS: fig:meas5 % [[file:figs/meas5.png]] % We compute the PSD of each track and we plot the PSD of the Z motion for the ground and marble on figure [[fig:meas5_z_psd]] and for the Y motion on figure [[fig:meas5_y_psd]]. [pxx51, f51] = pwelch(meas{5}.Track1(:), psd_window, [], [], Fs); [pxx52, f52] = pwelch(meas{5}.Track2(:), psd_window, [], [], Fs); [pxx53, f53] = pwelch(meas{5}.Track3(:), psd_window, [], [], Fs); [pxx54, f54] = pwelch(meas{5}.Track4(:), psd_window, [], [], Fs); figure; hold on; plot(f51, sqrt(pxx51)./abs(squeeze(freqresp(L4C_G, f51, 'Hz')))); plot(f52, sqrt(pxx52)./abs(squeeze(freqresp(L4C_G, f52, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); legend({meas{5}.Track1_Name, meas{5}.Track2_Name}, 'Location', 'northwest'); hold off; % #+LABEL: fig:meas5_z_psd % #+CAPTION: PSD of the ground and marble in the Z direction % #+RESULTS: fig:meas5_z_psd % [[file:figs/meas5_z_psd.png]] figure; hold on; plot(f53, sqrt(pxx53)./abs(squeeze(freqresp(L4C_G, f53, 'Hz')))); plot(f54, sqrt(pxx54)./abs(squeeze(freqresp(L4C_G, f54, 'Hz')))); xlim([fmin, fmax]); xticks([1, 10, 100]); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); xlabel('Frequency [Hz]'); ylabel('PSD [$m/s/\sqrt{Hz}$]'); legend({meas{5}.Track3_Name, meas{5}.Track4_Name}, 'Location', 'northwest'); hold off; % #+LABEL: fig:meas5_y_psd % #+CAPTION: PSD of the ground and marble in the Y direction % #+RESULTS: fig:meas5_y_psd % [[file:figs/meas5_y_psd.png]] % Then, instead of looking at the Power Spectral Density, we can try to estimate the transfer function from a ground motion to the motion of the marble. % The transfer functions are shown on figure [[fig:meas5_tf]] and the coherence on figure [[fig:meas5_coh]]. [tfz, fz] = tfestimate(meas{5}.Track1(:), meas{5}.Track2(:), psd_window, [], [], Fs); [tfy, fy] = tfestimate(meas{5}.Track3(:), meas{5}.Track4(:), psd_window, [], [], Fs); figure; ax1 = subplot(2,1,1); hold on; plot(fz, abs(tfz)); plot(fy, abs(tfy)); set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); set(gca, 'XTickLabel',[]); ylabel('Magnitude'); hold off; ax2 = subplot(2,1,2); hold on; plot(fz, 180/pi*angle(tfz)); plot(fy, 180/pi*angle(tfy)); set(gca,'xscale','log'); yticks(-180:90:180); ylim([-180 180]); xlabel('Frequency [Hz]'); ylabel('Phase [deg]'); hold off; linkaxes([ax1,ax2],'x'); xlim([fmin, fmax]); legend({'Z direction', 'Y direction'}, 'Location', 'southwest') % #+LABEL: fig:meas5_tf % #+CAPTION: Transfer function estimation - measurement 5 % #+RESULTS: fig:meas5_tf % [[file:figs/meas5_tf.png]] [cohz, fz] = mscohere(meas{5}.Track1(:), meas{5}.Track2(:), psd_window, [], [], Fs); [cohy, fy] = mscohere(meas{5}.Track3(:), meas{5}.Track4(:), psd_window, [], [], Fs); figure; hold on; plot(fz, cohz); plot(fy, cohy); hold off; set(gca, 'XScale', 'log'); set(gca, 'YScale', 'lin'); ylabel('Coherence'); xlabel('Frequency [Hz]'); xlim([fmin, fmax]); legend({'Z direction', 'Y direction'}, 'Location', 'southwest')