Modeling and control of magnetic flexible rotor bearing system

The dynamics of a flexible non-uniform rotor supported by two 3-pole active magnetic bearings (AMB) is modeled by integrating generalized polynomial expansion method (GPEM) and eigen mode method. The assumed modes required for the eigen mode method are obtained by GPEM. A stabilizing levitation controller is designed for the system. The controller is designed based on the model with only two assumed modes. The feedback linearization and integral sliding mode control (ISMC) are integrated for the controller design to overcome the effects of nonlinearity and uncertainty. Simulations are carried out to verify the proposed modeling method and robust controller, including the influences of uncertainties caused by un-modeled dynamics.