Plot Bode diagrams from the given closed loop system frequency responses in the table

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Anele 2024-9-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2155595-plot-bode-diagrams-from-the-given-closed-loop-system-frequency-responses-in-the-table

评论： Anele 2024-9-30

I am stuck here, I am able to plot the bode diagram from a TF and yet given closed loop system frequency responses I get stumped. Is there a video or link where I can learn more about coding these types of Bode diagrams?

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Sam Chak 2024-9-26

Please type out the data, and provide the formulas for the Bode plot. The task should be relatively easy.

Anele 2024-9-27

在 MATLAB Online 中打开

I ended up using the following method to obtain the Bode Plot

% Clear and close all figures and variables
clear all; close all; clc;
% Define given experiment frequency response data 
% Define experimental frequency points (in rad/s)
frequencies = [10000 1.0308e+04 1.2054e+04 1.4096e+04 1.6484e+04 1.9276e+04 2.2541e+04 2.6360e+04 3.0825e+04 3.6046e+04 4.2152e+04 4.9292e+04 5.7641e+04 6.7405e+04 7.8823e+04 9.2175e+04 100000 1.0779e+05 1.2005e+05 1.3500e+05 1.4978e+05 1.6422e+05 1.7816e+05 1.9149e+05 2.0412e+05 2.1759e+05 2.3387e+05 2.5373e+05 2.7818e+05 3.0864e+05 3.4707e+05 3.7691e+05 4.4076e+05 5.1542e+05 6.0272e+05 7.0482e+05 8.2420e+05 9.6381e+05 1000000 1.1271e+06 1.3180e+06 1.5412e+06 1.8023e+06 2.1076e+06 2.4646e+06 2.8821e+06 3.3703e+06 3.9411e+06 4.6087e+06 5.3894e+06 6.3023e+06 7.3698e+06 8.6182e+06 10000000];
% Define system output magnitudes A_o at corresponding frequencies
magnitudes = [10.0135 10.0144 10.0196 10.0269 10.0368 10.0503 10.0689 10.0943 10.1293 10.1773 10.2434 10.3345 10.4606 10.6358 10.8801 11.2226 11.4527 11.7038 12.1432 12.7459 13.3949 14.0372 14.5954 14.9805 15.1185 14.9411 14.2493 12.8606 10.8411 8.5495 6.3902 5.1965 3.5394 2.4476 1.7163 1.2168 0.8698 0.6256 0.5793 0.4520 0.3276 0.2380 0.1732 0.1263 0.0921 0.0672 0.0491 0.0359 0.0262 0.0192 0.0140 0.0102 0.0075 0.0056];
% Define system output phase shifts φ_o at corresponding frequencies (degrees)
phases = [-1.7215 -1.7747 -2.0765 -2.4302 -2.8450 -3.3319 -3.9043 -4.5785 -5.3748 -6.3185 -7.4427 -8.7906 -10.4217 -12.4199 -14.9089 -18.0793 -20.0954 -22.2383 -25.9347 -31.0784 -37.0062 -43.7533 -51.2698 -59.3831 -67.7922 -77.2447 -88.7365 -101.7827 -115.2116 -127.6625 -138.2902 -144.0139 -152.0947 -157.7617 -161.9207 -165.0911 -167.5801 -169.5783 -169.9920 -171.2094 -172.5573 -173.6815 -174.6252 -175.4215 -176.0957 -176.6681 -177.1550 -177.5698 -177.9235 -178.2253 -178.4830 -178.7032 -178.8913 -179.0446];  
% Convert magnitude to decibels for the Bode magnitude plot
magnitudes_dB = 20*log10(magnitudes);
% Plot Bode Magnitude (Gain) plot
subplot(2, 1, 1);
semilogx(frequencies, magnitudes_dB, 'b');
grid on;
title('Bode Diagram - Magnitude');
xlabel('Frequency (rad/s)');
ylabel('Magnitude (dB)');
% Plot Bode Phase plot
subplot(2, 1, 2);
semilogx(frequencies, phases, 'r');
grid on;
title('Bode Diagram - Phase');
xlabel('Frequency (rad/s)');
ylabel('Phase (degrees)');

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Answer 1

Paul 2024-9-28

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2155595-plot-bode-diagrams-from-the-given-closed-loop-system-frequency-responses-in-the-table#answer_1524245

移动：Paul 2024-9-29

在 MATLAB Online 中打开

If you store the data in a frd object, then we can use toolbox functions to make the plot and save some code

% Define given experiment frequency response data

% Define experimental frequency points (in rad/s)

frequencies = [10000 1.0308e+04 1.2054e+04 1.4096e+04 1.6484e+04 1.9276e+04 2.2541e+04 2.6360e+04 3.0825e+04 3.6046e+04 4.2152e+04 4.9292e+04 5.7641e+04 6.7405e+04 7.8823e+04 9.2175e+04 100000 1.0779e+05 1.2005e+05 1.3500e+05 1.4978e+05 1.6422e+05 1.7816e+05 1.9149e+05 2.0412e+05 2.1759e+05 2.3387e+05 2.5373e+05 2.7818e+05 3.0864e+05 3.4707e+05 3.7691e+05 4.4076e+05 5.1542e+05 6.0272e+05 7.0482e+05 8.2420e+05 9.6381e+05 1000000 1.1271e+06 1.3180e+06 1.5412e+06 1.8023e+06 2.1076e+06 2.4646e+06 2.8821e+06 3.3703e+06 3.9411e+06 4.6087e+06 5.3894e+06 6.3023e+06 7.3698e+06 8.6182e+06 10000000];

% Define system output magnitudes A_o at corresponding frequencies

magnitudes = [10.0135 10.0144 10.0196 10.0269 10.0368 10.0503 10.0689 10.0943 10.1293 10.1773 10.2434 10.3345 10.4606 10.6358 10.8801 11.2226 11.4527 11.7038 12.1432 12.7459 13.3949 14.0372 14.5954 14.9805 15.1185 14.9411 14.2493 12.8606 10.8411 8.5495 6.3902 5.1965 3.5394 2.4476 1.7163 1.2168 0.8698 0.6256 0.5793 0.4520 0.3276 0.2380 0.1732 0.1263 0.0921 0.0672 0.0491 0.0359 0.0262 0.0192 0.0140 0.0102 0.0075 0.0056];

% Define system output phase shifts φ_o at corresponding frequencies (degrees)

phases = [-1.7215 -1.7747 -2.0765 -2.4302 -2.8450 -3.3319 -3.9043 -4.5785 -5.3748 -6.3185 -7.4427 -8.7906 -10.4217 -12.4199 -14.9089 -18.0793 -20.0954 -22.2383 -25.9347 -31.0784 -37.0062 -43.7533 -51.2698 -59.3831 -67.7922 -77.2447 -88.7365 -101.7827 -115.2116 -127.6625 -138.2902 -144.0139 -152.0947 -157.7617 -161.9207 -165.0911 -167.5801 -169.5783 -169.9920 -171.2094 -172.5573 -173.6815 -174.6252 -175.4215 -176.0957 -176.6681 -177.1550 -177.5698 -177.9235 -178.2253 -178.4830 -178.7032 -178.8913 -179.0446];

h = frd(magnitudes.*exp(1j*phases*pi/180),frequencies);

bodeplot(h)