High precision low speed control of magnetically suspended reaction flywheel

For solving the problem of high precision request and the difficulty of low speed control of Magnetically Suspended Reaction Flywheel (MSRW), optical encoder is applied into MSRW to measure the rotate speed of motor. A input current control scheme based on disturbance observer is proposed to suppress the influence from the current ripple and the beating of rotor at low speed. High precision speed feedback can be gotten when adopts optical encoder measuring the rotate speed of motor at low speed. The input current waveform can be improved effectively when applies the disturbance observer into the input current control. The validity of the scheme is verified by experiment. Experiment results show that speed feedback and control precision have been improved greatly by applying optical encoder and disturbance observer into the MSRW control system, which will be important for realizing the high precision and high steady satellite attitude control.