A nonlinear output feedback control method for magnetic bearing systems

In this paper, a nonlinear output feedback control method is proposed for a magnetic bearing system which has a strong nonlinearity in the magnetic bearing system which has a strong nonlinearity in the magnetic actuator. The basic idea is to make full use of the feature that the dynamics part is linear and hence can be stabilized by output of the actuator is regarded as a virtual input. Then it is shown that the backstepping and completing square techniques enable the construction of the construction of the real input using measured output only.