Rate-dependent Hammerstein model and H_∞ robust tracking control of giant magnetostrictive actuators

A Hammerstein model is proposed to model the rate-dependent hysteresis nonlinearity of giant magnetostrictive actuators (GMA). A modified Prandtl-Ishlinskii (MPI) model and an autoregressive model with exogenous input (ARX) are used to represent the static nonlinear part and the linear dynamic part of the Hammerstein model, respectively. A model identification method is also given. The proposed model can describe the rate-dependent hysteresis of GMA from 1 Hz to 100 Hz well. A two DOF control system with an inverse compensator and an H1 robust controller is designed for tracking control. Real-time trajectory tracking control results show that the proposed strategy is effective.