Load-dependent hysteresis of magnetostrictive materials

A load-dependent hysteresis model for magnetostrictive materials is studied. Magnetostrictive materials are a class of smart materials which react with a magnetic field and are suitable for many micro-positioning actuation tasks. Unfortunately, these materials are difficult to use because of their highly nonlinear and hysteretic response. Unlike the hysteresis seen in magnetic materials, the shape of the hysteresis curve changes significantly if the load is changed. Because of this complex hysteresis, magnetostrictive actuators are difficult to control. To achieve sub-micron accuracy for micropositioning, an accurate hysteresis model is needed. The model studied in this paper is similar to the Preisach model. By modeling the Gibbs energy for each dipole and the equilibrium states, hysteresis in magnetostrictive materials is modeled. The model is implemented in a way that different hysteresis curves are generated if the load is changed. Using experimental data, optimum model parameters are obtained. The model results and experimental data were compared at different loads. A modification is proposed for more accuracy and the modified model is compared to the original model.