electrostatic levitation;  sliding mode control;  sliding mode observer;  electrostatic force;  Robust control

According to the gyro rotor mechanics equation, a rotordynamic model considering the change of system parameters is established, and a discrete sliding mode observer and integral discrete sliding mode controller are designed, and MATLAB SIMULINK is used for dynamic simulation and compared with linear control. The results show that after sliding mode control, the overshoot in the time domain is reduced by 40% and the adjustment time is shortened by 60%. The frequency domain stiffness is increased by 42% in the low frequency band, 110% at the lowest point in the middle frequency band, and 53% in the high frequency band, which significantly enhances the system’s ability to suppress external disturbances. After the introduction of the boundary layer, the jitter of the control voltage is greatly weakened, the accuracy of system control is improved, and the energy loss is reduced. Therefore, sliding mode control can improve the dynamic performance of the system, and has strong robustness under the influence of parameter changes and external disturbances in the system.