Output argument error while using musyn

Hello.

I built a block diagram using the function "connect" . This function take as input sumblk , weight function and state space.

Then I used the commande hinfsyn :

load('workspace')
[K,CL,gamma]=hinfsyn(model,1,1);

Which worked, but when I try to use the same model with the command musyn i get this error :

[Krob,rpMU] = musyn(model,1,1) 

Output argument "nag1" (and possibly others) not assigned a value in the execution with "mkargs5x" function.

Error in musyn (line 88)
[emsg,nag1,xsflag,Ts,A,B1,B2,C1,C2,D11,D12,D21,D22,w,gamind,aux,logd0,n,blksz,flag]=mkargs5x('tss',varargin); error(emsg);

In the documentation Robust Control of Active Suspension the same model is used for both functions and it works.

Thanks for your time

Answer 1

[Matthieu]

Hello,

Your attached file does not contain uncertainties in your model when transitioning from H-inf control to Mu-synthesis.

See the Matlab example Robust control of Active Suspension. This code snippet

unc = ultidyn('unc',[1 1],'SampleStateDim',5);
Act = ActNom*(1 + Wunc*unc);

introduces uncertainties in the active suspension actuator model.

H-inf method guarantees peformance for the nominal actuator model ; mu-synthesis achieves robust performance, it guarantees performance for all actuators comprised in the uncertainty specified.

In the example given by Mathworks, there is a comparison for the response of the controller to a road bump between robust control using mu-synthesis and nominal control using H-inf that is very useful to seize the difference.