Finite-Time Convergent Multiple Disturbance Rejection Control for Electromechanical Actuators

Electromechanical actuators (EMA) composed of permanent magnet synchronous motors are extensively employed in aircraft applications. However, several multisource disturbances in EMAs bring barriers to the high-dynamic position servo systems. Most of the existing disturbance rejection methods for EMAs converge exponentially and focus on a constant disturbance. However, practical disturbances, such as load torque, are high-order. To this end, this article puts forward a novel finite-time convergent nonlinear function, enhancing the dynamic tracking performance of the servo systems. Then a novel extended state observer (ESO) is proposed to improve the estimation accuracy of high-order disturbances. The integration of the composite controller and the ESO form the multiple disturbance rejection control method, which achieves error convergence in finite time. Finally, simulation and experimental results are provided to verify the effectiveness of the proposed method.