Modeling of an SMA actuator based on the Liang and Rogers model

Abstract

The purpose of this study is to develop a complete mathematical model of a thick shape memory alloys (SMA) actuator based on the Liang and Rogers model. Due to hysteresis and significant nonlinearities in the behavior of shape memory alloy actuators, the modeling of SMA actuators has been a great challenge in recent years, which limit the application of these actuators. In this paper, a new model is used to represent the major and minor hysteresis loops of SMA actuator based on the Liang and Rogers model. The modified Liang and Rogers model of SMA wire actuated by an electric current is derived and several experiments are used to validate the model and to identify the parameters. A key feature of the proposed model is to predict the martensite starting temperature of minor loops. This model can be used to develop a position control system for the SMA actuator. Simulation results for the model are found to be in good agreement with experimental data.