ADRC of Halbach Maglev Linear Motor Based on Second-Order Nonsingular Fast Terminal Sliding Mode for Unmanned Handling System

Aiming at the high-precision positioning requirements of the unmanned material handling system (UMHS), this paper focuses on addressing the challenges of unsatisfactory anti-disturbance performance and chattering during the motion process of the permanent magnet moving-type Halbach maglev linear motor (PMM-HMLM). In this paper, a dual-loop control method is proposed based on second-order nonsingular fast terminal sliding mode (SONFTSM) to improve the sliding mode (SM) surface and reaching law function of the conventional SM control (SMC). Furthermore, a nonlinear extended state observer (NLESO) is introduced to observe and compensate for disturbances, enabling integrated design of position and speed controllers to enhance the motor dynamic response. Simulations and experiments are conducted to analyze the dynamic and static characteristics of PMM-HMLM under SMC and sliding mode active disturbance rejection control (SMADRC), respectively. The results demonstrate that the SMADRC dual-loop control method effectively improves the system anti-disturbance performance and suppresses chattering compared to SMC.