Fixed‐time dual sliding mode control for linear synchronous motor maglev systems

Abstract

AbstractA dual fixed‐time terminal sliding mode control strategy is proposed to address the problems of magnetic coupling, end effects and unknown disturbances in linear synchronous motor maglev systems, which ensures that the system tracking trajectory achieves fixed‐time convergence and high accuracy. First, a fixed‐time integral terminal sliding mode surface is designed to obtain the desired dynamic properties and avoid the singularity problem. Second, based on the dynamic sliding mode theory, a second fixed‐time terminal sliding mode surface is designed to weaken the chattering problem in the controller by replacing the discontinuous switching signal with a continuous switching rule. The proposed controller is theoretically proved to be fixed‐time convergent and the convergence time is independent of the initial conditions by means of the Lyapunov function and the fixed‐time convergence theorem. Finally, simulations and experiments are carried out on a linear maglev experimental platform. Compared with the fixed‐time sliding mode control, the simulation and experimental results show that the proposed strategy improves the tracking accuracy by 37.5%, the convergence speed by 33.3%, and the robustness by 42.1%, which has the advantages of fast convergence speed, strong robustness, and weak chattering.