Fuzzy modeling and control of a nonlinear magnetic bearing system

This paper deals with the control of a levitated object with position dependent nonlinearity. We applied the fuzzy modeling and control to a nonlinear magnetic bearing system to obtain uniform desired performance over the entire clearance. We represented the nonlinear magnetic bearing by the Takagi-Sugeno-Kang (TSK) fuzzy model, where a nonlinear global model is approximated by a set of linear local models. Then a model-based fuzzy controller, the so-called parallel distributed compensation (PDC), is employed. Simulation and experimentation results demonstrate that the controller provides excellent compensation for unstable/nonlinear characteristics of the magnetic bearing system and maximizes the controller's valid region of operation, while guaranteeing pre-specified transient performance.