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How can I combine these two MATLAB codes? (MATLAB)

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Santa Fe
Santa Fe on 7 Jan 2021
Commented: Adam Danz on 8 Jan 2021
I want to show step function and ramp function in one matlab code.
clc; %unit step function
clear;
G1 = tf([1], [5, 1]);
G2 = tf([1], [1, 0]);
G3 = series(5, G1);
G4 = feedback(G3, 0.8);
G = series(G4, G2);
sys = feedback(G, 1);
t = 0:0.001:25;
r = ones(1, length(t));
y2 = lsim(sys, r, t);
plot(t, y2, 'linewidth', 2);
grid;
xlabel('Time, t (s)');
ylabel('Amplitude');
title('Plot of y_2(t)');
clc; %ramp function
clear all;
close all;
s=tf('s');
C=5*(1+0.8*s)
P=1/(s*(5*s+1))
CL=feedback(C*P,1)
figure;
step(CL)
t=0:0.1:10;
r=t;
[y,t]=lsim(CL,r,t);
figure;
plot(t,y,'linewidth',2);
title('Ramp Response');

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Accepted Answer

Adam Danz
Adam Danz on 7 Jan 2021
Edited: Adam Danz on 7 Jan 2021
This should get you started,
s=tf('s');
C=5*(1+0.8*s);
P=1/(s*(5*s+1));
CL=feedback(C*P,1);
figure
step(CL)
ax = gca();
hold(ax,'on')
G1 = tf([1], [5, 1]);
G2 = tf([1], [1, 0]);
G3 = series(5, G1);
G4 = feedback(G3, 0.8);
G = series(G4, G2);
sys = feedback(G, 1);
t = 0:0.001:25;
r = ones(1, length(t));
y2 = lsim(sys, r, t);
plot(t, y2, 'linewidth', 2,'DisplayName','y2');
t=0:0.1:10;
r=t;
[y,t]=lsim(CL,r,t);
plot(t,y,'linewidth',2,'DisplayName','Ramp Response');
ylim(ax,[-inf,max(y)])
% The first legend string is based on your variable name "CL".
legend('Location','NorthWest')
Alternatively,
[yResp, TOut] = step(CL);
plot(TOut, yResp)

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More Answers (1)

the cyclist
the cyclist on 7 Jan 2021
Use the hold command
figure
hold on
plot(t, y2, 'linewidth', 2);
plot(t,y,'linewidth',2);
and then your other commands for labels, etc

  1 Comment

Adam Danz
Adam Danz on 8 Jan 2021
Unfortunately there's no way to prevent the step() function from producing its own figure unless outputs are included which won't produce a plot at all.

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