Improved Model-Free Sliding Mode Control of Linear Motor Based on Time-Varying Gain Model-Assisted Linear Extended State Observer

Aiming at the effects of motor parameter ingress and load mutation on the speed control of permanent magnet synchronous linear motor (PMSLM) motors, this paper designs a PMSLM improved model-free sliding-mode speed control strategy based on the variable-gain model-assisted linear expansion observer (TMLESO). First, time-varying gain-based model-assisted linear expansion observer (MLESO) is designed to improve the accuracy of LESO generalized perturbation estimation. Next, the TMLESO is constructed by combining the MLESO and the time-varying function to solve the problem of large initial peaks. Finally, a model-free sliding-mode velocity controller with adaptable boundary layer thickness is constructed to reduce the effect of sliding-mode jitter on velocity tracking and improve the dynamic performance of the system. The effectiveness of the proposed control strategy is analyzed through simulations and experiments.