MATLAB: Is there a hinfsyn replacement

h-infinityhinfsynobsoleterobustRobust Control Toolbox

Is there a replacement/updated version of the function hinfsyn? It looks like hinfsyn is now classed as obsolete(?) – if I run:
which hinfsyn
one of the subdirectories in the file path is called 'rctobsolete'. I ask this as the function doesn't seem to work properly. Depending on the generalised plant I've defined, P, sometimes:
[K,CL,gam,info] = hinfsyn(P,ny,nu);
works as expected, but sometimes it spits out variables K, CL, gam and info that are just empty arrays(!) – it doesn't display any warnings or errors, it just produces nothing. Does anyone know what's happening here?
Is there a newer 'replacement' function for H-infinity synthesis?
Thanks, Oliver

Best Answer

The 'hinfsyn' function is good to use, usually the documentation page shows warning when a function is planned to be replaced in the future release.
When the 'hinfsyn' function returns empty, it means that it did not find any controller that could meet your specifications.
I have informed the relevant team to consider adding a warning or throw an error in this case in a future release.
Hope this helps,
Janak
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