Lsim with two input signal

I have this system

 A = [ 1  1 -1 ; 0  -1  1 ; 0  1  -1 ];
B = [ 1  0 ; 0  1 ; 0  0 ];
C = [ 1  0  0 ];
D = [ 0 ] ;
sys = ss( A , B , C , D )

Now i have to put two signals in input with lsim the two signals are u1( t ) = 2*square( t ) and u2( t ) = 0 i have written something like this

    figure( 2 ) ;
t = 0:0.01:10 ;
u = [ 2*square( t ) ];
u2 = zeros( size( t ) ) ; 
sys2 = tf( sys ) ;
lsim( sys2 , u , t , x0 );

but i continue to have this error

Error using DynamicSystem/lsim (line 97) 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 have tried many ways but i don't know what to do it there isn't nothing on the internet on multi input with lsim please help !

I thank in advance any of you

Answer 1

[Aveek Podder]

Hi,

The input matrix B defined is a 3x2 Matrix, by doing this we have defined a two-input system. For lsim to function as expected we need to pass both the inputs. The error message says the same.

To resolve the issue pass both the input, please use the following command:

>> lsim( sys2 , [u;u2] , t , x0 );

For more information on lsim please have a look at the following link:

https://www.mathworks.com/help/control/ref/lsim.html

[thiago rech]

Great! What about systems with multiple outputs?