Error occurs while executing state space parameters using idss?

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.

Answer 1

[Mischa Kim]

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).

[PARASSURAM]

Thanks for your reply. but it seems i still getting the same error. is there any other way to solve this model, instead of idss?

[Mischa Kim]

Please post the entire code.

[PARASSURAM]

clear all clc r1=2.4 tg1=0.08 tt1=0.3 kp1=120 tp1=20 t12=0.545 a12=-1 tg2=0.08 r2=2.4 tt2=0.3 kp2=120 tp2=20 b1=0.4 b2=0.4

% REFERENCE SIGNAL r0

ref1=0

ref2=0

% LOAD PL

PL1=0.05

PL2=0.05

% SIMULATION TIME

time=60

% STATE SPACE VARIABLES [A,B,C,D,K]

 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 0]
 K=[0 0 -kp1/tp1 0 0 0 0; 0 0 0 0 0 0 -kp2/tp2]

% STATE SPACE CONVERSION

SYS1 = idss(A,B,C1,D,K)

SYS2 = idss(A,B,C2,D,K)

im trying to implement this system in mpc controller.

[PARASSURAM]

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]

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.