Adaptive control based on variant operating-point linearization in magnetic bearings of mscmg

To improve stability of magnetically suspended rotor system in magnetically suspended control moment gyroscope (MSCMG) at high gimbal rotation speed, linearization of nonlinear force-current-displacement characteristic and relevant control algorithm of magnetic bearing (MB) are investigated. Operating point variation of MB with gimbal rotation is analyzed, and a novel method of variant operating-point linearization referring to gimbal speed is proposed. Linear parameter varying model of MB is achieved and adaptive control algorithm incorporating gain-scheduled and feedforward corresponding to gimbal speed is designed to compensate displacement stiffness rising due to gimbal running and current asscending, which increases gimbal speed from 6.25 (°)/s to 9.5 (°)/s under condition of stable MB-rotor system according to experimental results. It can be concluded that the proposed method can compensate MB force nonlinearity and improve MB-rotor system stability significantly at high gimbal speed.