The auto-disturbance rejection controller for speed regulation in permanent-magnet linear motors

This paper presents a novel robust control strategy for the speed regulation of a permanent-magnet linear motor (PMLM) based on direct feedback linearization. This method takes into account both the uncertainties in the model and the uncertainties from the outside environment as the unknown disturbances to the system. These unknown disturbances are estimated through an extended state observer (ESO). A nonlinear state error feedback control law (NLSEF) is designed according the estimated disturbances. With the proposed auto-disturbance rejection controller (ADRC), the disturbance can be compensated and nonlinear system can be decoupled into linear subsystems. The control law only has relationships with the reference input and the output Therefore the control is much simplified with fewer variables detected. The feasibility and robustness of the proposed control method is verified by simulation.