Abstract: “In this paper, a feedforward-feedback controller is used to control the position of an SMA actuator based on a modified Liang and Rogers inverse model, considering both the major and minor hysteresis loops. First a modified Liang and Rogers model of an SMA wire actuated by an electric current is derived and experiments are used to validate the model and to identify the parameters governing its behavior. Then the feedforward part of the proposed control system, which is based on this inverse model, is used to compensate the hysteresis effect, and a PID controller is added to the feedforward controller to increase the accuracy as well as reduce the steady state errors in the position control process. Experimental results demonstrate that the proposed control system performs better than when only a traditional PID controller is used.”

Keywords: SMA actuator, inverse hysteresis compensation, position control