simulate State Space system with lsim

A = [0 1 0 0; 0 0 1 0; 0 0 0 1; -2 -5 -7 -2];
B = [0; 0; 0; 1];
C = [1 3 0 0];
D = 0;

t = 10;

sys = ss(A,B,C,D);

x0 = [1 1 1 1];
 u = exp(-0.3*t)*sin(t);

lsim(sys, u, t)
grid

I was given this ss system, but it keeps returning:

Error using DynamicSystem/lsim (line 97)
When simulating the response to a specific input signal, the input data U must be a matrix of numeric values with at least two
rows (samples) and without any NaN or Inf.

Error in HW2_2b (line 15)
lsim(sys, u, t)

Any ideas?

Answer 1

[Star Strider]

For a SISO system, ‘t’ needs to be a vector:

t = linspace(0,10);

the full code being:

A = [0 1 0 0; 0 0 1 0; 0 0 0 1; -2 -5 -7 -2];
B = [0; 0; 0; 1];
C = [1 3 0 0];
D = 0;

t = linspace(0,10);

sys = ss(A,B,C,D);

x0 = [1 1 1 1];
 u = exp(-0.3*t).*sin(2*pi*t);

lsim(sys, u, t)
grid

Create ‘t’ to be whatever you want.