Error using DynamicSystem/lsim

0 down vote favorite I am running a dynamic system but I got an error saying:

Error using DynamicSystem/lsim (line 84)
    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 while evaluating UIControl Callback

My code is

[vabls.ResponseYdata vabls.ResponseXdata] = lsim(vabls.ctf,vabls.numinput,vabls.tset);

My U and T are both same as 1x501 sym and 1x501 double. My sys is

             814500
    ------------------------
    s^2 + 361.2 s + 8.145e05

where numerator is [0,0,814500] and deniminator is [1,361.2000,8.1450e+05]

Answer 1

[Star Strider]

‘My U and T are both same as 1x501 sym and 1x501 double.’

They should both be double. Neither should be sym.

[David Ling]

Thank you very much!

[Star Strider]

As always, my pleasure!

[youma]

Hello @Star Strider I'm having a look alike error with my code.

function [cost, ceq] = drone_costfunction(x, systemea, yref, Q, R, t, u)

    Q(1,1) = x(1);
    Q(3,3) = x(2);
    Q(5,5) = x(3);
    R(1,1) = x(4);
    R(2,2) = x(5);

    K = lqr(systemea.A, systemea.B, Q, R);
    sys_cl = ss(systemea.A - systemea.B*K, systemea.B, systemea.C, systemea.D);
    
    y = lsim(sys_cl, u, t); %where the error occurs 
    
    ceq = [];
    cost = sum((yref-y(:,1)).^2);

end

knowing that u and t, are taken with

[yref,y,u,t] =sys(A,B,C,D) 
 size(u)

ans =

    94     1
 size(t)

ans =

    94     1

"Error using DynamicSystem/lsim

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.

I can't seem to understand what can possibly be wrong here. Thanks in advance for your help.

[Star Strider]

I can’t determine what the problem is, however the ‘B’ matrix likely has more than one column (input channel).

To get a definitive response, post this as a new Question, and supply the function arguments, preferably as a .mat file. Without those, it can’t be run or simulated.

Stopping here.