how to control amplitude of step in code

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? ....

Answer 1

[Star Strider]

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));

.

Answer 2

[Mathieu NOE]

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]

you can do this as soon as the system is linear in (amplitude ) response (LTI systems for example)