Research on giant magnetostrictive micro-displacement actuator with self-adaptive control algorithm

Abstract

Giant magnetostrictive micro-displacement actuator has some unique characteristics, such as big output torque and high precision localization which can be in the nanometer scale. Because the relation between input magnetic field and output strain of giant magnetostrictive micro-displacement actuator exhibits hysteresis and eddy flow, the actuator has to be controlled and used in low input frequency mode or in static mode. When the actuator is controlled with a high input frequency (above 100 Hz), the output strain will exhibit strong nonlinearity. This paper found hysteresis and nonlinearity dynamic transfer function of the actuator based on Jiles-Atherton hysteresis model. The output strain of Jiles-Atherton hystersis model can reflect real output of actuator corresponding to the real input magnetic field, and this has been verified by experiment. Against the nonlinearity generated by hysteresis and eddy flow in this paper, the output strain of actuator is used for feedback to control system, and the control system adopted self-adaptive control algorithm, the ideal input and output model of actuator is used for a reference model and a hysteresis transfer function for the actuator real model. Through experiment, it has been verified that this algorithm can improve the dynamic frequency of the giant magnetostrictive micro-displacement actuator and guarantee high precision localization and linearity between the input magnetic field and output strain of the actuator at the same time.