Error occurs while executing state space parameters using idss?

5 views (last 30 days)
i'm new to state space modelling. while i try to execute A,B,C,D,E parameters using idss, it displays the error as " The sizes of state-space parameter matrices must be consistent with size and order of the model. "
The code i used in m file are as follows
A=[-1/tg1 0 -1/(tg1*r1) 0 0 0 0; 1/tt1 -1/tt1 0 0 0 0 0; 0 kp1/tp1 -1/tp1 -kp1/tp1 0 0 0; 0 0 t12 0 0 0 -t12; 0 0 0 0 -1/tg2 0 -1/(r2*tg2); 0 0 0 0 1/tt2 -1/tt2 0; 0 0 0 -(a12*kp2)/tp2 0 kp2/tp2 -1/tp2]
B=[1/tg1 0 0 0 0 0 0; 0 0 0 0 1/tg2 0 0]'
C1=[0 0 1 0 0 0 0]
C2=[0 0 0 0 0 0 1]
D=0
K=[0 0 -kp1/tp1 0 0 0 0; 0 0 0 0 0 0 -kp2/tp2]'
SYS1 = idss(A,B,C1,D,K)
SYS2 = idss(A,B,C2,D,K)
Can anyone help me?
Thanks in advance.

Accepted Answer

Mischa Kim
Mischa Kim on 10 Oct 2014
Edited: Mischa Kim on 10 Oct 2014
PARASSURAM, check the size of the matrices.
It looks like your D matrix needs to be a 1-by-2 (rather than a 1-by-1). K should be a 2-by-7 (rather than 7-by-2).
  5 Comments
PARASSURAM
PARASSURAM on 10 Oct 2014
I have found my mistake. 'K' should be used as two matrix. Like, K1=[0 0 -kp1/tp1 0 0 0 0] K2=[0 0 0 0 0 0 -kp2/tp2]
Qandeel
Qandeel on 25 Mar 2015
Edited: Qandeel on 25 Mar 2015
I am also facing problems when using the idss command. Can you tell how do you find the output and states when you define a system by the idss command instead of ss command. The 'lsim' does not work with idss.

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!