Robust Nonlinear Servo Control of Permanent Magnet Synchronous Motor Based on Finite-time Extended State Observer

In this paper, a nonlinear servo control method based on finite-time observer is developed for position control of permanent magnet synchronous motor (PMSM). The nonlinear servo control law consists of two parts, where the linear part is responsible for the fast dynamic response and the nonlinear part is responsible for reducing the overshoot when the system approaches the steady state. To tackle the time-varying uncertainty occurring in the system, a finite-time extended state observer is proposed to estimate the lumped disturbance for feed-forward compensation in the control loop. Simulation and experimental results verify that the proposed control scheme can track the target position quickly and accurately, and is robust against disturbance and uncertainty.