Reducing Conservatism for Gain Scheduled H Controllers for AMB s

We address the problem of H gain scheduling of a magnetic bearing rotor system with the speed of the rotor being the scheduling parameter The rotor exhibits signi cant gyroscopics As a result the plant dynamics change with the rotor speed Recent results in the theory of LPV systems can be used to design robust gain scheduled controllers for such a system As opposed to traditional gain scheduling LPV controllers o er guarantees of stability and performance over the whole range of the rotor speed However these control laws can be overly conservative since they ensure stability for arbitrarily fast variations in the scheduling parameter In this paper we re ne these LPV controllers in order to obtain better bounds on the achievable performance in the presence of a priori known bounds of the variation of the rotor speed