MATLAB: Get empty results from hinfsyn

empty resultsh∞ robust controlhinfsynMATLABRobust Control Toolbox

Hi all,

I have used the hinfsyn function several times before without any problem. But recently I am working on a new project that I decided to implement H∞ robust controller. For some reason, the code returns empty values of K, CL, GAM, and INFO according to the following syntax:

[K,CL,GAM,INFO] = hinfsyn(P,NMEAS,NCON,'GMIN',gamma_min);

where P is my system matrices based on hinfsyn help, NMEAS is the number of measured outputs, NCON is the number of control inputs, and gamma_min is my desired minimum gamma.

As said above, I do not know why it keeps giving me absolutely empty values without any errors or warnings!

Has anyone had similar problem before? What could potentially be wrong?

Thanks and I look forwarding to getting some help.

Best Answer

Actually, I accidentally solved the problem but still I do not know what was the reason. My matrix A is full rank, the system is both controllable and observable. I made a little tweak and problem was resolved. I gave very very small values to a few zero elements of matrix A and it worked.

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MATLAB: Problem with if else loop

There are a couple issues I see.

You have too many end keywords. You only need two here.
To test multiple conditions, you have to separate them and as single conditions and join them using & (and) or } (or)

dt=0.01; %change in time increments
g=9.81; %acceleration due to gravity
u=0; %variable u is the kinetic friction constant, for asphalt is 0.7, for ice is 0.07*exp(0.06*v)
% a=-u*g acceleration, calculated from the free body diagram
t=0:dt:10.0;%time in seconds taken for the car to fully stop (v=0)    
v=zeros(1,length(t));
s=zeros(1,length(t));
v(1)=25;%velocity
s(1)=0;%displacement
for k= 2:length(t)
    
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        a=-u*g;
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    elseif v(k)<0.0
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end 
disp(v);
figure
subplot(2,1,1)
plot(t(1:k),v(1:k));
title('Velocity vs time');
ylabel('Velocity(m/s)');
xlabel('Time(s)');
subplot(2,1,2)
plot(t(1:k),s(1:k));
xlabel('Time(s)');
ylabel('Displacement(m)');
title('Displacement vs time');

MATLAB: Logical Indexing Within a Symbolic Array

Try this

syms w1 w2 w3 w4 w5 w6 w7 w8 w9 w10
A = [0 0 0 w7 0 0;
     0 0 0 0 w9 0;
     0 w3 0 0 0 0;
     0 0 w5 0 0 0;
     w1 0 w6 w8 0 0;
     w2 w4 0 0 w10 0];
A_bin = ~isAlways(A==0)

A_bin = ~isnan(A./A)

Best Answer

Related Solutions

MATLAB: Problem with if else loop

MATLAB: Logical Indexing Within a Symbolic Array

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