Implementation Of Robust Feedback Linearization On Active Magnetic Bearing Actuators

Feedback linearization is a promising approach to solve the nonlinear control problem for active mag- netic bearing systems. In this paper, feedback lin- earization is employed in combination with robust control techniques for the regulation of a machine tool system actuated by a magnetic bearing. A nonlinear, high order polynomial model was devel- oped based on experimental calibration of the mag- netic bearing. The e®ect of the ampli¯er and sen- sor dynamics on the feedback linearization perfor- mance was also determined and compensated. Fi- nally, an uncertainty framework was proposed for the linearized plant and a robust controller was de- signed via ¹ synthesis. Experimental results show that the feedback-linearized active magnetic bearing system can achieve both high performance as well as stability over the entire bearing clearance.