Modified Fixed-Time Extended State Observer Based Fixed-Time Sliding Mode Control for PMSM Position Servo Systems

Aiming to optimize the tracking and anti-disturbance capacities of permanent magnet synchronous motor (PMSM) position control systems, a modified fixed-time extended state observer (MFESO) based fixed-time sliding mode control (FSMC) algorithm is proposed in this paper. Firstly, the FSMC controller is constructed to enable the motor to accurately track the time-varying reference position signal. Secondly, the MFESO with a recursive structure is applied to estimate the total disturbance of the PMSM position servo system to reduce its adverse effects. By compensating the estimation value of the disturbance to the FSMC scheme, a smaller control gain can be selected to obtain satisfactory anti-disturbance performance, thereby reducing the chattering. Furthermore, rigorous Lyapunov stability analysis demonstrates that the motor position and speed tracking error can converge to zero in fixed time. Finally, experimental results under different types of reference signals and disturbance verify that the proposed position control scheme delivers outstanding performance.