Input Signal from state space model

im just wondering how can i plot the input signal of a state space model? and also how do i include a step reference signal for my input channel?

A = [    0         0         0    1.0000         0         0
         0         0         0         0    1.0000         0
         0         0         0         0         0    1.0000
         0    6.5000  -10.0000  -17.5000         0         0
  -21.1185   18.1040    5.1540   -3.6920   -2.8128    0.3159
    5.0000   -3.6000         0         0         0  -10.9545];

B =[     0         0
         0         0
         0         0
   26.5000   11.2000
    5.5907   -1.6525
   40.0000   57.3000];

C = [1     0     0     0     0     0
     0     1     0     0     0     0
     0     0     1     0     0     0];

D = 0;

Answer 1

[Sam Chak]

Hi @Justin

You can try using the lsim() function. Search Google/Documentation for details. Example is shown below:

A = [    0         0         0    1.0000         0         0;
         0         0         0         0    1.0000         0;
         0         0         0         0         0    1.0000;
         0    6.5000  -10.0000  -17.5000         0         0;
  -21.1185   18.1040    5.1540   -3.6920   -2.8128    0.3159;
    5.0000   -3.6000         0         0         0  -10.9545];
B = [    0         0;
         0         0;
         0         0;
   26.5000   11.2000;
    5.5907   -1.6525;
   40.0000   57.3000];
C = [1     0     0     0     0     0;
     0     1     0     0     0     0;
     0     0     1     0     0     0];
D = 0;
sys = ss(A, B, C, D);

Tp     = 1;                                 % 1 cycle period
Tf     = 1;                                 % final time simulation
Ts     = 1e-4;                              % sample time
[u, t] = gensig('sine', Tp, Tf, Ts);
lsim(sys, [heaviside(t - 0.25), -2*u], t)   % 1st input is step, 2nd input is sine