Adaptive trajectory tracking of magnetostrictive actuator based on preliminary hysteresis compensation and further adaptive filter controller

Abstract

The magnetostrictive actuator is a widely used precision smart actuator; however, the micro-positioning and tracking performance of it is limited due to the inherent dynamic nonlinearities. In order to improve the tracking performance of actuator, a hybrid control strategy comprising a preliminary rate-independent hysteresis compensation and a further adaptive filter controller is developed. The generalized Prandtl–Ishlinskii model that has analytical inversion is used to preliminarily compensate the rate-independent hysteresis. A modified coral reef optimization algorithm is utilized to identify the model parameter and accordingly enhance the compensation accuracy. In addition, considering the input current and output displacement of magnetostrictive actuator are always positive, a one-side generalized play operator is adopted. Further, the adaptive finite impulse response controller is applied to eliminate the preliminary compensation error which is owing to the dynamic effect of nonlinearities. In order to validate the hybrid control strategy, some simulations and experiments are conducted. Compared with the feedforward inverse controller, the hybrid control strategy is of better accuracy and adaptivity. The results demonstrate that the hybrid control strategy is capable of precisely tracking step and multiple-frequency sinusoidal trajectory.