High-Order Fast Nonsingular Terminal Sliding Mode Control of Permanent Magnet Linear Motor Based on Double Disturbance Observer

In order to realize the high-speed and high-precision movement of the direct drive system, it is important to study the strong robust control strategy of permanent magnet linear synchronous motor (PMLSM) servo system. This article proposes a high-order fast nonsingular terminal sliding mode control strategy for PMLSM based on double disturbance observer. The double disturbance observer is used to observe the mismatched/matched disturbances to reduce the conservativeness of the system to multiple disturbances. In addition, a high-order fast nonsingular terminal sliding mode controller is designed to enhance the robustness of the system. By adding feedback current into the controller, the overall control of current, speed, and position is realized. In addition, the steady-state performance and dynamic performance of position tracking system are improved. The stability and convergence of the closed loop system are proved by the Lyapunov stability theory. Experimental results show that the proposed strategy can effectively improve position tracking accuracy of the system and robustness to uncertain disturbances.