A Nonlinear Output Feedback Control Method for a 5DOF Active Magnetic Bearing System

摘要

A nonlinear dynamic output feedback control method for a 5-degree-of-freedom active magnetic bearing system is presented in this paper. This method guarantees the asymptotic stability of the closed loop system with arbitrarily low bias current. The basic idea is to make full use of the feature that the dynamics part is linear and hence can be stabilized by output feedback when the output of actuator is regarded as the virtual input of the linear dynamics. Then, a quadratic-like Lyapunov function is proposed for the nonlinear design of control voltage and it is shown that backstepping and completing square techniques enable the construction of the voltage input by using the measured output only.