MATLAB Answers


Robust Controller Badly Scaled

Asked by Drvoljub
on 4 Oct 2011


I have a problem with my H-Infity controller. I run the code but I get the error that the matrix is badly scaled and close to singular.

% Number of measurements
nmeas = 2;
% Number of controls
ncon = 1;
% lower bound of bisection
gmin = 0.15;
% Upper bound of bisection
gmax = 1000000000;
hin_ic = sel(sys_ic,8:11,8:11);
tol = 0.00001;
% hinfsyn command is used to compute the H-Infinty controller
[K_hin,clp] = hinfsyn(hin_ic,nmeas,ncon,gmin,gmax,tol);
disp(' ')

I dont get how this produces a gamma value of 984192557.2224. It should be like 400000. Also i dont know why gmax should be so high. When i put it lower i get the error that it is too low.

I hope some one can give me a hint.



1 Answer

Answer by Özgür
on 4 Jan 2013


I think you are using some weights and performance filters on your model. So chheck your performance filters that should not have any pole on rigt half plane.

Other important issue may be you need to small modify on your system.


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