Position Decoupling Control of Rigid Rotor of Active Magnetic Bearing

The magnetic bearing rotor system has the problem of positional coupling in the direction of the radial degrees of freedom. This paper proposes a linear output feedback method which decouples the multi-variable coupling system into four single-degree-of-freedom second-order integral subsystems. Firstly, a five-degree-of-freedom(5-DOF) mathematical model of active magnetic bearing rotor is derived. Then, a sliding mode variable structure controller is designed for the decoupled subsystems and the stability of system is guaranteed by the Lyapunov stability theory. The results of computer simulation show that the design controller of sliding mode variable structure controller can more effectively enhance the magnetic bearing rotor performance stability compared with the conventional PD controller, fuzzy PD controller, no matter in the position respond control and anti-disturbance control. Moreover, the sliding mode variable structure controller make the system have better tracking performance.