# how to control amplitude of step in code

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RJS on 23 Dec 2021
Answered: Star Strider on 4 Jan 2022
I have A B C D matrix
G7 =ss(A,K*B,C,D)
t = [0:0.001:5]';
[y, t, x] = step(feedback(G7,(Ka + 1/s)),t);
plot(t, x(:,3));
here K and Ka are control gains, in my actual plant angle is input to the system but when we perform step command that time it gives output response for one radian.............
.But I want step response for different amplitude ,How to do? ....

Star Strider on 4 Jan 2022
Use stepDataOptions to create an options structure, and specifically the StepAmplitude option —
A = randn(3) % Create System
A = 3×3
-0.3929 -0.4093 -1.4841 -2.2959 -0.3964 -0.7033 0.7378 -2.0547 -1.0544
B = rand(3,1) % Create System
B = 3×1
0.7772 0.3109 0.7188
C = rand(1,3) % Create System
C = 1×3
0.0152 0.0333 0.6986
D = 0; % Create System
K = rand % Create System
K = 0.6582
Ka = rand % Create System
Ka = 0.9986
s = tf('s');
G7 =ss(A,K*B,C,D)
G7 = A = x1 x2 x3 x1 -0.3929 -0.4093 -1.484 x2 -2.296 -0.3964 -0.7033 x3 0.7378 -2.055 -1.054 B = u1 x1 0.5115 x2 0.2046 x3 0.4731 C = x1 x2 x3 y1 0.0152 0.03335 0.6986 D = u1 y1 0 Continuous-time state-space model.
t = [0:0.001:5]';
opts = stepDataOptions('StepAmplitude',5)
opts =
step with properties: InputOffset: 0 StepAmplitude: 5
[y, t, x] = step(feedback(G7,(Ka + 1/s)),t, opts);
plot(t, x(:,3)); .

Mathieu NOE on 4 Jan 2022
hello
simply multiply the result of the (normalized) step (input amplitude = 1) by the actual / desired input amplitude
input_amplitude = 0.3; % your value here
G7 =ss(A,K*B,C,D);
t = [0:0.001:5]';
[y, t, x] = step(feedback(G7,(Ka + 1/s)),t);
plot(t, input_amplitude*x(:,3));
Mathieu NOE on 4 Jan 2022
you can do this as soon as the system is linear in (amplitude ) response (LTI systems for example)