Accuracy of Hysteresis Modeling in Smart Actuator with MSMA

This paper is focused on hysteresis modeling in actuator with magnetic shape memory alloy, briefly MSMA. MSMAs are new group of active materials which change shape in external magnetic field. Active element is made of Ni2MnGa, and it is very suitable to use in actuators for positioning, because this alloy combines great strains (up to 6%) and good dynamic properties. On the other side, it is distinguished by nonlinear behavior. In this case, it is wide saturated asymmetric hysteresis. Reason for that is a kind of internal friction called twining stress. Such drawback does not allow to precise position control in open-loop control system. Described in this paper method for hysteresis modeling is based on mathematical formulation, which utilizes so-called phenomenological models. Hysteresis modeling is provided by generalized Prandtl-Ishlinskii model (GPIM) where hyperbolic tangents were used as envelop functions in play operator. This paper describes modeling accuracy for different GPIM structures. Actuator is designed for high-strain applications up to 1 mm. Data acquisition was provided by dSPACE system.