Developing a fast response SMA-actuated rotary actuator: modeling and experimental validation

Shape memory alloy (SMA) applications as actuators are welcome nowadays due to their interesting properties. However, low speed and nonlinear behavior are two drawbacks of SMA. In order to overcome the latter disadvantages, this paper focuses on modeling, identification, and simulation of a fast response SMA-actuated rotary actuator. Genetic algorithm (GA) is used to identify unknown parameters of the model. In order to validate the model, a set-up is designed to provide experimental data. Using a pair of SMA wires in an antagonistic configuration helps improving the actuation speed and to reach bidirectional rotation without using springs. Furthermore, three modes of air convection cooling procedure are applied to the mechanism in order to provide faster responses. Finally, it is shown that the fast response rotary actuator is able to work within 5 Hz frequency bandwidth input electrical current providing 4° angle of rotation in high air convection cooling mode.