Adaptive Fault-Tolerant Control of Linear Motors Under Sensor and Actuator Faults

Permanent magnet linear synchronous motors (PMLSMs), as key drivers in the field of transportation, have a significant impact on the efficiency and reliability of transportation systems. This is due to their excellent performance in tracking accuracy and fault tolerance. Nevertheless, during long periods of operation, PMLSMs may potentially exhibit a multitude of actuator and sensor failures due to demagnetization, wearing, reduction of electromechanical constants, and component performance attenuation, among others. To solve this issue, this article addresses the problem of adaptive fault-tolerant control (AFTC) of PMLSMs under external disturbances and faults in sensors and actuators. An algorithm is proposed to estimate and compensate for sensor and actuator faults using the robust adaptive fault-tolerant method. Moreover, a nonlinear adaptive estimation control is designed to estimate lumped disturbances, including external unknown disturbances and uncertainties caused by system faults. For practical validation purposes, experiments have been carried out in a PMLSM platform. The obtained results demonstrate that the proposed method has excellent fault tolerance and tracking performance in the presence of system faults. When both faults and disturbances occur concurrently, the tracking accuracy of the proposed method outperforms that of the general control algorithm by more than 30%. It can be concluded that the proposed AFTC of PMLSMs can effectively reduce the problems of performance attenuation and security threats caused by actuator and sensor faults.