VIBRATION AND CONTROL OF A FLEXIBLE ROTOR IN MAGNETIC BEARINGS USING HYBRID METHOD AND H-INFINITY CONTROL-THEORY

The vibration and active control of a flexible rotor system with magne tic bearings are investigated using Hybrid Method (HM) and H-infinity control theory with consideration of gyroscopic effect. The hybrid met hod, which combines the merits of the finite element method (FEM) and generalized polynomial expansion method (GPEM) is employed to model th e flexible rotor system with small order of plant. The mixed sensitivi ty problem of H-infinity control theory is applied to design the contr ol of system vibration with spillover phenomena for the reduced order plant. The H-2 control design is also employed for comparison with the H-infinity design. The experimental simulation is used to illustrate the effects of control design. It is shown that the H-infinity control ler effective to suppress spillover phenomena. In addition, the H-infi nity control design has robustness to the variation of the model param eters. The application of the hybrid method (HM) together with H-infin ity control design is highly recommended for vibration control of flex ible rotor systems with magnetic bearings.