How to connect the simulink to fmincon? Thanks

Hello, everyone. I am a matlab learner. I have some proble associated with the combination with the simulink and fmincon. Thank you for any suggestion and helps.

Here is the code:

function main
close all; clc;
x0=[1.6   100];  
Lbnd=[0.5  90] ;
Ubnd=[2.5  450] ;
[x,y,exitflag,output]=fmincon(@objtime,x0,[],[],[],[],Lbnd,Ubnd,@Constt)
end

function ftime=objtime(x)
Kpi=x  
options = simset('SrcWorkspace','current');
[t,xstatus,y]=sim('control_a2') 
ftime=y(:,3)
end

function [C,Ceq]=Constt(x)
C(1)=x(1)-2.5  
C(2)=0.5-x(1)  
C(3)=x(2)-450  
C(4)=50-x(2)   
Ceq=[]         
end

The simulink is called in object function. But when I run the code. The "x" design variables are not changed. The optimization is not implemented. I am not sure whether is related with the workspace problem or with other aspects? Could you give me some idea and solution?

Thank you.

Answer 1

[Walter Roberson]

In your function "main", you assign to x, y, and so on, but those are local variables, so their values are thrown away after "main" runs. You may need to use something such as assignin('base','x',x)

[J T]

Hi Walter, 100% correct.

But I am just crious about the reason. It seems that I can ignore the "assignin" if no simulink model is called for main function.

Thank you

[Walter Roberson]

Sorry I do not know how Simulink really interfaces.