Nonlinear Active Disturbance Rejection Position Control of FJ-PMSM Based on an Enhanced High-Order Nonlinear Extended State Observer

To address the frequency-domain characteristic deficiencies in traditional active disturbance rejection position control (ADRC) systems, an enhanced nonlinear ADRC strategy is proposed in the paper. The paper improves the extended state observer (ESO) and feedback control law. The linear feedback control law constrained by both proportional and derivative-proportional gains is employed, while a fourth-order enhanced nonlinear extended state observer (EH-NESO) is designed based on the nonlinear ESO framework. The proposed method combines nonlinear functions and disturbance derivative observation techniques, exhibiting superior dynamic response performance and control stability under certain conditions. Experimental validation on the flexible joint permanent magnet synchronous motor (FJ-PMSM) demonstrates that the position control strategy proposed in the paper exhibits outstanding disturbance rejection performance.