idss state space model

Hello, everyone. I have a state space model which im trying to code into a matlab script:

A=[-Rr/Lr 0; 0 -Rr/Lr]; Ar=double(A);

B=[1/Lr 0; 0 1/Lr]; Br=double(B);

Bd=[1 0; 0 1]; Brd=double(Bd);

C=[1 0; 0 1; 0 0; 0 0]; Cr=double(C);

D=[0 0; 0 0; 1 0; 0 1]; Dr=double(D);

The Brd matrix here is a disturbance matrix. Now when i try to run the command: sysr=idss(Ar,Br,Cr,Dr,Brd), i get an error saying: "The sizes of state-space parameter matrices must be consistent with size and order of the model".

I have more outputs here than the # of states. Is that the issue? Thanks

Answer 1

[Jean]

Matrix Ar says it has 2 states, matrix Br says it has 2 inputs, but matrix Cr says it has 4 states and matrix Dr says it has 4 outputs!