Plot now showing correctly
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I was working on my code like 10 days ago in 2025a, the code is running and the plot is showing correctly. I decided to run again to take some screenshot of my plot but my plot is no longer displaying correctly. If I print the plot, I will see the correct plot on the print dialog but the original plot window is showing up very bad. Screenshot applied. Please any immediate help will be appreciated as this is my school assignment.
My computer is Linux Ubuntu 22.04
clear all; close all; clc;
%% System Parameters
% Physical parameters of the DC motor
Ra = 1.0; % Armature resistance (Ohm)
La = 0.5; % Armature inductance (H)
J = 0.01; % Moment of inertia (Nms^2/rad)
b = 0.1; % Damping coefficient (Nms)
KT = 0.01; % Torque constant (Nm/A)
Ke = 0.01; % Back EMF constant (Nm/A)
K = Ke; % In SI units, Ke = Ki = K
%% Transfer Function Definition
% Open loop transfer function: θ(s)/Ea(s)
% G(s) = K / [(Js + b)(Las + Ra) + K^2]
% Coefficients calculation
num = K;
den_coeff = [J*La, (J*Ra + b*La), (b*Ra + K^2)];
den = den_coeff;
% Create transfer function
G = tf(num, den);
% Display the transfer function
fprintf('Open Loop Transfer Function:\n');
fprintf('G(s) = %.4f / (%.4fs^2 + %.4fs + %.4f)\n', num, den(1), den(2), den(3));
%% Performance Specifications
% Desired specifications:
% - Settling time (Ts) < 2 seconds
% - Percentage Overshoot (PO) < 5%
% - Steady State Error (SSE) < 1%
fprintf('\nDesired Specifications:\n');
fprintf('- Settling time (Ts) < 2 seconds\n');
fprintf('- Percentage Overshoot (PO) < 5%%\n');
fprintf('- Steady State Error (SSE) < 1%%\n\n');
%% Step 1: Open Loop Response
fprintf('=== STEP 1: OPEN LOOP RESPONSE ===\n');
figure(1);
[y1, t1] = step(G);
plot(t1, y1, 'b-', 'LineWidth', 2);
title('Open Loop Step Response');
xlabel('Time (seconds)');
ylabel('Angular Position (rad)');
grid on;
% Calculate performance metrics for open loop
stepinfo_ol = stepinfo(G);
fprintf('Open Loop Performance:\n');
fprintf('Rise Time (Tr): %.4f seconds\n', stepinfo_ol.RiseTime);
fprintf('Settling Time (Ts): %.4f seconds\n', stepinfo_ol.SettlingTime);
fprintf('Peak Overshoot: %.2f%%\n', stepinfo_ol.Overshoot);
% Steady state error calculation (for unit step)
% For Type 0 system: ess = 1/(1+Kp) where Kp = lim s->0 G(s)
Kp_ol = dcgain(G);
ess_ol = 1/(1+Kp_ol) * 100; % Convert to percentage
fprintf('Steady State Error: %.2f%%\n', ess_ol);
fprintf('Comments: Open loop system is unstable or has poor performance\n\n');
Bad Plot
Print Dialog
7 commentaires
Your code works correctly here and in MATLAB Online --
clear all; close all; clc;
%% System Parameters
% Physical parameters of the DC motor
Ra = 1.0; % Armature resistance (Ohm)
La = 0.5; % Armature inductance (H)
J = 0.01; % Moment of inertia (Nms^2/rad)
b = 0.1; % Damping coefficient (Nms)
KT = 0.01; % Torque constant (Nm/A)
Ke = 0.01; % Back EMF constant (Nm/A)
K = Ke; % In SI units, Ke = Ki = K
%% Transfer Function Definition
% Open loop transfer function: θ(s)/Ea(s)
% G(s) = K / [(Js + b)(Las + Ra) + K^2]
% Coefficients calculation
num = K;
den_coeff = [J*La, (J*Ra + b*La), (b*Ra + K^2)];
den = den_coeff;
% Create transfer function
G = tf(num, den);
% Display the transfer function
fprintf('Open Loop Transfer Function:\n');
fprintf('G(s) = %.4f / (%.4fs^2 + %.4fs + %.4f)\n', num, den(1), den(2), den(3));
%% Performance Specifications
% Desired specifications:
% - Settling time (Ts) < 2 seconds
% - Percentage Overshoot (PO) < 5%
% - Steady State Error (SSE) < 1%
fprintf('\nDesired Specifications:\n');
fprintf('- Settling time (Ts) < 2 seconds\n');
fprintf('- Percentage Overshoot (PO) < 5%%\n');
fprintf('- Steady State Error (SSE) < 1%%\n\n');
%% Step 1: Open Loop Response
fprintf('=== STEP 1: OPEN LOOP RESPONSE ===\n');
figure(1);
[y1, t1] = step(G);
plot(t1, y1, 'b-', 'LineWidth', 2);
title('Open Loop Step Response');
xlabel('Time (seconds)');
ylabel('Angular Position (rad)');
grid on;
% Calculate performance metrics for open loop
stepinfo_ol = stepinfo(G);
fprintf('Open Loop Performance:\n');
fprintf('Rise Time (Tr): %.4f seconds\n', stepinfo_ol.RiseTime);
fprintf('Settling Time (Ts): %.4f seconds\n', stepinfo_ol.SettlingTime);
fprintf('Peak Overshoot: %.2f%%\n', stepinfo_ol.Overshoot);
% Steady state error calculation (for unit step)
% For Type 0 system: ess = 1/(1+Kp) where Kp = lim s->0 G(s)
Kp_ol = dcgain(G);
ess_ol = 1/(1+Kp_ol) * 100; % Convert to percentage
fprintf('Steady State Error: %.2f%%\n', ess_ol);
fprintf('Comments: Open loop system is unstable or has poor performance\n\n');
.
Samuel
le 14 Juil 2025
Déplacé(e) : Steven Lord
le 14 Juil 2025
If I remember correctly, The MathWorks uses Ubuntu here and in MATLAB Online.
ver
.
Samuel
le 14 Juil 2025
Star Strider
le 14 Juil 2025
I ran it again in MATLAB Online just now three times in succession, and it continues to plot correctly every time.
Omar
le 24 Oct 2025
Déplacé(e) : Dyuman Joshi
le 24 Oct 2025
Did you solved it, I have the same problem with Matlab R2025b
@Omar, Can you enter "computer" at the Command Window or provide the info about your computer on which MATLAB is running?
computer
Réponses (1)
IBE PETER
le 29 Oct 2025
Déplacé(e) : Walter Roberson
le 29 Oct 2025
0 votes
I was able to solve it by using a different linewidth in the plot command. plot(t1, y1, 'b-', 'LineWidth', 2); Change that 2 to like 0.5
1 commentaire
DGM
le 30 Oct 2025
This appears to be a known bug:
I can't find anything in the bug reports though.
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