Sliding Mode Based Controller for Magnetostrictive Actuator

Magnetostrictive actuator, for its merits of relatively low voltage and high force, has been increasingly applied in many applications, such as vibration control, aviation, positioner, etc. At low drive level, magnetostrictive actuator presents linear relation between strain or displacement and input voltage or input current, while non-linear appears when applied moderate or high drive level. To achieve accurate control for high drive level, non-linear, including saturation and hysteresis, must be compensated. Sliding mode control, a robust control scheme, can handle these non-linear. As magnetostrictive actuator modelled in Jiles-Atherton model, the relation of magnetic field H and bulk magnetization M, hysteresis, is divided into anhysteresis and deviation from anhysteresis. Saturation can be compensated by inversion of anhysteresis (free-hysteresis) and then, hysteresis, represented as the deviation from anhysteresis, is compensated with sliding mode control. In section I, introduction of magnetostrictive actuator characters and compensation methods for its non-linear is presented. Then, Jiles-Atherton model based on domain wall theory is introduced in section II. Next, the design procedures of sliding-mode controller are given. Control law for GMA position tracking is derived as well. Simulation and its results are shown in Section IV. And the conclusion is made at Section V.