Please help!!!!Error: Failure in initial nonlinear constraint function evaluation. FMINCON cannot continue.

I am trying to run this code but Im getting a bunch of errors.

t=0:.1:5;

u(1:25)=.1;

u(26:51)=-.1;

plot(t,u);

[to,yo]=sim('hw',5,[],[t',u']);

%Finding u_final and cost

l_b=ones(51,1)*(-50);

u_b=ones(51,1)*50;

options=optimset('Display','iter','PlotFcns','optimplotx');

[u_final,cost]=fmincon('find_cost',u,[],[],[],[],l_b,u_b,'find_constraint',options);

[t_f,x_f,y_f]=sim('hw',5,[],[t' u_final']);

These are the functions used

%Cost function

function cost=find_cost(u)

cost=(1/2)*.1*trapz(u.*u);

end

%Constraint function with constraint x(5)=15

function [cineq,ceq]=find_constraint(u)

cineq=[];

t=0:.1:5;

[tout,yout]=sim('hw',t',[],[t',u']);

ceq(1)=15-yout(end,1);

ceq(2)=yout(end,2);

ceq(3)=yout(end,3);

ceq(4)=yout(end,4);

ceq(5)=yout(end,5);
end

Kindly help me I need to do this..

Answer 1

[Walter Roberson]

Your code assumes that find_constraint is being passed a row vector, u, but fmincon makes not such guarantee. The documentation says that the nonlinear constraint function must accept a vector or array, but there is no documentation about when it will be any particular shape.

I recommend that you use

[tout,yout]=sim('hw',t',[],[t',u(:)]);

[Aishwarya Bangalore Kumar]

I m still getting the same errors

[Walter Roberson]

I would need your simulink model to test further.

[Aishwarya Bangalore Kumar]

That is the simulink model for the program.

[Walter Roberson]

>> sim('simfig')
No system or file called 'simfig' found. 
>> sim('simfig.PNG')
The file name 'simfig.PNG' is invalid because it does not have the extension ".mdl" or ".slx". 
>> !cp simfig.PNG simfig.mdl
>> sim('simfig')
Warning: simfig.mdl, line 1: Unexpected characters at or before line 1, column 8 
File '/Users/roberson/MATLAB/3/384/384494/simfig.mdl' does not contain a valid Simulink model 
>> !cp simfig.PNG simfig.slx
>> sim('simfig')
File '/Users/roberson/MATLAB/3/384/384494/simfig.slx' does not contain a valid Simulink model in SLX format: Could not open source package

Your model seems to have been corrupted when you attached it.

[Aishwarya Bangalore Kumar]

i think its because i could not attach the format of a simulink model the 'slx' its simfg.slx

[Walter Roberson]

You can zip the model and attach the zip