Problem with using lsim which lead to row and column error ?

Upon running my code which is :

A = [0,1;0,0]; B2 = [0;64013000]; Cc = [-10.588174398921385,-0.318818010164237]; Bc = [2.409919108480979e3;4.696699700129756e2]; C2 = [1,0]; Ac = [-2.409587000245264e3,1.000000016273038;-6.777812774681246e8,-2.040849728464332e7];

B1 = [0,0;1,0]; D21 = [0,1];

C1 = [1,0;0,0]; D12 = [0;0.100000000000000];

Acl = [A B2*Cc ; Bc*C2 Ac]; Bcl = [B1 ; Bc*D21]; Ccl = [C1 D12*Cc]; Dcl = zeros(2,2);

clsys = ss(Acl, Bcl, Ccl, Dcl);

t = 0:0.01:10; w = zeros(1, length(t)); k = 1;

for n = 1:length(t) if k < 100 w(k) = 0; elseif k >= 100&&k <= 301; w(k) = 1; else w(k) = 0; end k = k+1; end

y = lsim(clsys, w, t); plot (t, y(1));

I ran into this error: "When simulating the response to a specific input signal, the input data U must be a matrix with as many rows as samples in the time vector T, and as many columns as input channels."

My w and t were clearly having the same row and column as indicated on the workspace. May I know what went wrong?

Answer 1

[Mischa Kim]

Hello Raymond, your system has two inputs, therefore w needs to be a 2-by-n array, rather than a 1-by-n. Use instead:

 ...
 t = 0:0.01:10; 
 w = zeros(2, length(t)); 
 k = 1;

 for n = 1:length(t) 
    if k < 100 
        w(:,k) = 0; 
    elseif k >= 100&&k <= 301; 
        w(:,k) = 1; 
    else w(:,k) = 0; 
    end
    k = k+1; 
 end

 y = lsim(clsys, w, t); 
 plot (t, y);

...and adapt to your needs as necessary.

[Raymond]

Thanks! It worked!