Continuous rotary motor actuated by multiple segments of shape memory alloy wires

An attempt has been made in this study to develop a continuous rotary motor actuated by multiple segments of shape memory alloy wires (SMA motor). In order to meet the requirements of continuous rotation, large output torque, and stall torque, a unidirectional rotary actuator was designed, and five rotary actuators were fixed on one shaft in series. When every actuator is actuated in turn, the SMA motor can realize a continuous rotation. In order to simulate the rotation angle, output torque, and the actuation performance degradation of the SMA motor, Lagoudas's constitutive model was modified to consider the cyclic actuation influence. After design and simulation, a prototype of the SMA motor was fabricated and experimentally tested to verify the feasibility and performance of the proposed design decision. The test results indicate that the SMA motor can realize continuous rotation. The rotation speed is 0.28 r/min, and the torque is 1008 N mm.