What is the error in my state space model?

Hi everyone, I have a state-space model here, which sent output u to MATLAB Function. Inside of MATLAB Function I declare Function [A,B,C,D] = input(u) and the if loop as the attached picture.

But when i run the simulation, It says invalid Matrix A in state space (I set A,B,C and D in each A,B,C,D block) Please tell me where is my mistake in my model/matlab function. Thank you in advance!!

Answer 1

[Azzi Abdelmalek]

The matrices A,B,C,D of your SS model should be set inside your SS block http://www.mathworks.com/help/simulink/slref/statespace.html#zmw57dd0e133327 , you can't set them as an entry of your system. The entries of your SS block are considered as the entry signals of your system.

[Chihhan Hou]

Thank you Azzi Abdelmalek. so actually I cant connect the matlab function to the input of SS block is that you mean? In that case, If I want to change the A,B,C,D matrices in ss block as the output U change, how can i do?

[Azzi Abdelmalek]

You have at least two options

1. Rewrite your state space model with other blocks like derivative, sum, etc...
2. Or you can use set_param function outside simulink

doc set_param