211 lines
6.6 KiB
Matlab
211 lines
6.6 KiB
Matlab
%% Clear Workspace and Close figures
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clear; close all; clc;
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%% Intialize Laplace variable
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s = zpk('s');
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%% Path for functions, data and scripts
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addpath('./mat/'); % Path for data
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addpath('./src/'); % Path for Functions
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%% Colors for the figures
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colors = colororder;
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%% Simscape model name
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mdl = 'rotating_model';
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%% Load "Generic" system dynamics
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load('rotating_generic_plants.mat', 'Gs', 'Wzs');
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%% Modified IFF - parameters
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g = 2; % Controller gain
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wi = 0.1; % HPF Cut-Off frequency [rad/s]
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Kiff = (g/s)*eye(2); % Pure IFF
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Kiff_hpf = (g/(wi+s))*eye(2); % IFF with added HPF
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%% Loop gain for the IFF with pure integrator and modified IFF with added high-pass filter
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freqs = logspace(-2, 1, 1000);
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Wz_i = 2;
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figure;
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tiledlayout(3, 1, 'TileSpacing', 'Compact', 'Padding', 'None');
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% Magnitude
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ax1 = nexttile([2, 1]);
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hold on;
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plot(freqs, abs(squeeze(freqresp(Gs{Wz_i}('fu', 'Fu')*Kiff(1,1), freqs, 'rad/s'))))
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plot(freqs, abs(squeeze(freqresp(Gs{Wz_i}('fu', 'Fu')*Kiff_hpf(1,1), freqs, 'rad/s'))))
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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set(gca, 'XTickLabel',[]); ylabel('Loop Gain');
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% Phase
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ax2 = nexttile;
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hold on;
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plot(freqs, 180/pi*angle(squeeze(freqresp(Gs{Wz_i}('fu', 'Fu')*Kiff(1,1), freqs, 'rad/s'))), 'DisplayName', 'IFF')
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plot(freqs, 180/pi*angle(squeeze(freqresp(Gs{Wz_i}('fu', 'Fu')*Kiff_hpf(1,1), freqs, 'rad/s'))), 'DisplayName', 'IFF,HPF')
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'lin');
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xlabel('Frequency [rad/s]'); ylabel('Phase [deg]');
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yticks(-180:90:180);
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ylim([-90 180]);
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xticks([1e-2,1e-1,1,1e1])
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xticklabels({'', '$0.1 \omega_0$', '$\omega_0$', '$10 \omega_0$'})
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leg = legend('location', 'southwest', 'FontSize', 8);
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leg.ItemTokenSize(1) = 15;
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linkaxes([ax1,ax2],'x');
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xlim([freqs(1), freqs(end)]);
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%% High-Pass Filter Cut-Off Frequency
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wis = [0.01, 0.05, 0.1]; % [rad/s]
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%% Root Locus for the initial IFF and the modified IFF
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gains = logspace(-2, 4, 200);
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figure;
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hold on;
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for wi_i = 1:length(wis)
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wi = wis(wi_i);
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Kiff = (1/(wi+s))*eye(2);
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L(wi_i) = plot(nan, nan, '.', 'color', colors(wi_i,:), 'DisplayName', sprintf('$\\omega_i = %.2f \\omega_0$', wi));
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for g = gains
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clpoles = pole(feedback(Gs{2}({'fu', 'fv'}, {'Fu', 'Fv'}), g*Kiff));
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plot(real(clpoles), imag(clpoles), '.', 'color', colors(wi_i,:),'MarkerSize',4);
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end
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plot(real(pole(Gs{2}({'fu', 'fv'}, {'Fu', 'Fv'})*Kiff)), ...
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imag(pole(Gs{2}({'fu', 'fv'}, {'Fu', 'Fv'})*Kiff)), ...
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'x', 'color', colors(wi_i,:),'MarkerSize',8);
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plot(real(tzero(Gs{2}({'fu', 'fv'}, {'Fu', 'Fv'})*Kiff)), ...
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imag(tzero(Gs{2}({'fu', 'fv'}, {'Fu', 'Fv'})*Kiff)), ...
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'o', 'color', colors(wi_i,:),'MarkerSize',8);
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end
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hold off;
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axis equal;
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xlim([-2.3, 0.1]); ylim([-1.2, 1.2]);
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xticks([-2:1:2]); yticks([-2:1:2]);
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leg = legend(L, 'location', 'southwest', 'FontSize', 8);
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leg.ItemTokenSize(1) = 8;
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xlabel('Real Part'); ylabel('Imaginary Part');
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clear L
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xlim([-1.25, 0.25]); ylim([-1.25, 1.25]);
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xticks([-1, 0])
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xticklabels({'$-\omega_0$', '$0$'})
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yticks([-1, 0, 1])
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yticklabels({'$-\omega_0$', '$0$', '$\omega_0$'})
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ytickangle(90)
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%% Compute the optimal control gain
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wis = logspace(-2, 1, 100); % [rad/s]
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opt_xi = zeros(1, length(wis)); % Optimal simultaneous damping
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opt_gain = zeros(1, length(wis)); % Corresponding optimal gain
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for wi_i = 1:length(wis)
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wi = wis(wi_i);
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Kiff = 1/(s + wi)*eye(2);
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fun = @(g)computeSimultaneousDamping(g, Gs{2}({'fu', 'fv'}, {'Fu', 'Fv'}), Kiff);
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[g_opt, xi_opt] = fminsearch(fun, 0.5*wi*((1/Wzs(2))^2 - 1));
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opt_xi(wi_i) = 1/xi_opt;
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opt_gain(wi_i) = g_opt;
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end
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%% Attainable damping ratio as a function of wi/w0. Corresponding control gain g_opt and g_max are also shown
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figure;
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yyaxis left
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plot(wis, opt_xi, '-', 'DisplayName', '$\xi_{cl}$');
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set(gca, 'YScale', 'lin');
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ylim([0,1]);
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ylabel('Damping Ratio $\xi$');
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yyaxis right
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hold on;
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plot(wis, opt_gain, '-', 'DisplayName', '$g_{opt}$');
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plot(wis, wis*((1/Wzs(2))^2 - 1), '--', 'DisplayName', '$g_{max}$');
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hold off;
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set(gca, 'YScale', 'lin');
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ylim([0,10]);
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ylabel('Controller gain $g$');
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xlabel('$\omega_i/\omega_0$');
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set(gca, 'XScale', 'log');
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legend('location', 'northeast', 'FontSize', 8);
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%% Compute damped plant
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wis = [0.03, 0.1, 0.5]; % [rad/s]
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g = 2; % Gain
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Gs_iff_hpf = {};
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for i = 1:length(wis)
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Kiff_hpf = (g/(wis(i)+s))*eye(2); % IFF with added HPF
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Kiff_hpf.InputName = {'fu', 'fv'};
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Kiff_hpf.OutputName = {'Fu', 'Fv'};
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Gs_iff_hpf(i) = {feedback(Gs{2}, Kiff_hpf, 'name')};
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end
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%% Effect of $\omega_i$ on the damped plant coupling
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freqs = logspace(-2, 1, 1000);
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figure;
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tiledlayout(3, 1, 'TileSpacing', 'Compact', 'Padding', 'None');
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% Magnitude
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ax1 = nexttile([2, 1]);
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hold on;
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for i = 1:length(wis)
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plot(freqs, abs(squeeze(freqresp(Gs_iff_hpf{i}('Du', 'Fu'), freqs, 'rad/s'))), '-', 'color', [colors(i,:)], ...
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'DisplayName', sprintf('$d_u/F_u$, $\\omega_i = %.2f \\omega_0$', wis(i)))
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plot(freqs, abs(squeeze(freqresp(Gs_iff_hpf{i}('Dv', 'Fu'), freqs, 'rad/s'))), '-', 'color', [colors(i,:), 0.5], ...
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'DisplayName', sprintf('$d_v/F_u$, $\\omega_i = %.2f \\omega_0$', wis(i)))
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end
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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set(gca, 'XTickLabel',[]); ylabel('Magnitude [m/N]');
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leg = legend('location', 'southwest', 'FontSize', 8, 'NumColumns', 1);
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leg.ItemTokenSize(1) = 20;
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ax2 = nexttile;
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hold on;
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for i = 1:length(wis)
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plot(freqs, 180/pi*angle(squeeze(freqresp(Gs_iff_hpf{i}('Du', 'Fu'), freqs, 'rad/s'))), '-')
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end
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'lin');
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xlabel('Frequency [rad/s]'); ylabel('Phase [deg]');
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yticks(-180:90:180);
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ylim([-180 0]);
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xticks([1e-2,1e-1,1,1e1])
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xticklabels({'$0.01 \omega_0$', '$0.1 \omega_0$', '$\omega_0$', '$10 \omega_0$'})
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linkaxes([ax1,ax2],'x');
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xlim([freqs(1), freqs(end)]);
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%% Effect of $\omega_i$ on the obtained compliance
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freqs = logspace(-2, 1, 1000);
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figure;
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tiledlayout(1, 1, 'TileSpacing', 'Compact', 'Padding', 'None');
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% Magnitude
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ax1 = nexttile();
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hold on;
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for i = 1:length(wis)
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plot(freqs, abs(squeeze(freqresp(Gs_iff_hpf{i}('Du', 'Fdx'), freqs, 'rad/s'))), '-', 'color', [colors(i,:)], ...
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'DisplayName', sprintf('$d_{x}/F_{dx}$, $\\omega_i = %.2f \\omega_0$', wis(i)))
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end
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plot(freqs, abs(squeeze(freqresp(Gs{2}('Du', 'Fdx'), freqs, 'rad/s'))), 'k--', ...
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'DisplayName', '$d_{x}/F_{dx}$, OL')
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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xlabel('Frequency [rad/s]'); ylabel('Compliance [m/N]');
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leg = legend('location', 'southwest', 'FontSize', 8, 'NumColumns', 1);
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leg.ItemTokenSize(1) = 20;
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xticks([1e-2,1e-1,1,1e1])
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xticklabels({'$0.01 \omega_0$', '$0.1 \omega_0$', '$\omega_0$', '$10 \omega_0$'})
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