Abstract: 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 ana-lyzed, and a novel method of variant operating-point lineariza-tion referring to gimbal speed is proposed. Linear parameter varying model of MB is achieved and adaptive control algo-rithm incorporating gain-scheduled and feedforward corre-sponding to gimbal speed is designed to compensate displace-ment 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.

Key words: Control moment gyroscope, Gain-scheduled, Linearization, Magnetic bearing, Moving-gimbal effects, Nonlinearity