Can anyone able to get me the step response from this code. I am trying to modify the initial response to step but unable to do so?

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Tenzing Thiley on 20 Apr 2022

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https://www.mathworks.com/matlabcentral/answers/1700785-can-anyone-able-to-get-me-the-step-response-from-this-code-i-am-trying-to-modify-the-initial-respo

Commented: Mathieu NOE on 20 Apr 2022

Accepted Answer: Tenzing Thiley

A = [ -0.040493 9.8689 0 -9.81;

-0.0021967 -0.030908 1 0;

-0.013639 -0.015207 -0.42801 0;

0 0 1 0];

B = [3.2952 0 0 0;0 -0.0020488 -0.068204 0]';

C = [1 0 0 1];

D = 0;

K = [0.021937 2.93 0.24659 -2.9163; 2.5565 1.3199 1.4874 -3.9318];

Ke = [-0.80034 0.82799 -0.34548 0.76847]';

AA = [A-B*K B*K; zeros(4,4) A-Ke*C];

BB = [B;0 0;0 0;0 0;0 0]

CC = [C 0 0 0 0];

sys = ss(AA, eye(8), eye(8), eye(8));

t = 0:0.01:120;

x = initial(sys, [1;0;1;0; 0 ;0 ;0 ;0],t);

x1 = [1 0 0 0 0 0 0 0]*x';

x2 = [0 1 0 0 0 0 0 0]*x';

x3 = [0 0 1 0 0 0 0 0]*x';

x4 = [0 0 0 1 0 0 0 0]*x';

subplot(2,2,1); plot(t,x1); grid

xlabel('t (sec)'); ylabel('∆V')

subplot(2,2,2); plot(t,x2); grid

xlabel('t (sec)'); ylabel('∆α')

subplot(2,2,3); plot(t,x3); grid

xlabel('t (sec)'); ylabel('∆q')

subplot(2,2,4); plot(t,x4); grid

xlabel('t (sec)'); ylabel('∆θ')

4 Comments
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Tenzing Thiley on 20 Apr 2022

When I am using step function step() I am getting an error can you modify instead of initial can you change to step input

Mathieu NOE on 20 Apr 2022

Open in MATLAB Online

A = [ -0.040493       9.8689            0        -9.81;
   -0.0021967    -0.030908            1            0;
    -0.013639    -0.015207     -0.42801            0;
            0            0            1            0];
B = [3.2952 0 0 0;0 -0.0020488 -0.068204 0]';
C = [1 0 0 1];
D = 0;
K = [0.021937         2.93      0.24659      -2.9163; 2.5565       1.3199       1.4874      -3.9318];
Ke = [-0.80034      0.82799     -0.34548      0.76847]';
AA = [A-B*K B*K; zeros(4,4) A-Ke*C];
BB = [B;0 0;0 0;0 0;0 0]
CC = [C 0 0 0 0];
sys = ss(AA, eye(8), eye(8), eye(8));
t = 0:0.01:120;
% x = initial(sys, [1;0;1;0; 0 ;0 ;0 ;0],t);
opt = stepDataOptions('StepAmplitude',0.1);
x = step(sys,t,opt);
subplot(2,2,1); plot(t,x(:,1)); grid
xlabel('t (sec)'); ylabel('∆V')
subplot(2,2,2); plot(t,x(:,2)); grid
xlabel('t (sec)'); ylabel('∆α')
subplot(2,2,3); plot(t,x(:,3)); grid
xlabel('t (sec)'); ylabel('∆q')
subplot(2,2,4); plot(t,x(:,4)); grid
xlabel('t (sec)'); ylabel('∆θ')