Hysteresis modeling and control system design for shape memory alloy actuators

This paper presents the hysteresis modeling of shape memory alloy actuators (SMA) using Maxwell resistive capacitor (MRC or Maxwell model). The SMA actuators exhibit nonlinearity between electrical input and output displacement. Its hysteretic behavior can cause inaccuracy in tracking if it is not modeled properly. Modified Maxwell model is adopted to compensate for the asymmetric hysteresis loop obtained from the experimental system. Control system design containing inverse Maxwell model is developed and experiments are conducted to verify the effectiveness of the dynamic model and controller.