Abstract:A permanent magnet synchronous linear motor (PMLSM) fixed-time control strategy based on state constraints is proposed for the speed and current double closed-loop control system of permanent magnet synchronous linear motor (PMLSM).The velocity tracking error of the system is constrained by an asymmetric obstacle Lyapunov function,and the fixed-time filter is designed without complex switching terms to overcome the′ differential explosion ′problem in traditional backstepping control.A fixed time disturbance observer is constructed to observe the load disturbance of the motor,and the disturbance is compensated to the control system to enhance robustness.Theoretical analysis proves that the system converges boundedly in a fixed time,and the velocity error can be constrained in a reasonable interval. Based on Matlab simulation experiment,when a sudden load is added at a given speed of 0.5 m/s,the speed tracking accuracy exceeds 98%,which is 2% higher than that of the fixed-time control strategy.The tracking range deviation of the disturbance observer is less than 1%,which has high observation accuracy.The simulation and experimental results verify the effectiveness of the control strategy in this paper.