Integrated adaptive robust control of active magnetic bearings

This paper presents an adaptive-robust approach to control of active magnetic bearing (AMB) systems subjected to parametric uncertainties and external disturbances. The control design uses sliding-mode method and therefore has the advantages of order reduction, disturbance rejection, insensitivity to parameter variation and simplicity of implementation. The design is based on the original nonlinear dynamic equations of the rotor and global stability of the closed loop system is guaranteed. The proposed approach integrates both adaptive and robust control where the adaptive design is used to cancel out the gravitational force and the force due to rotor mass imbalance and the robust design is used to compensate for other disturbances and improve the transient performance. Numerical simulations are provided to demonstrate the efficacy of the proposed control.