A review of rotary actuators based on shape memory alloys

The development of rotary actuators is an important aspect of the engineering applications of shape memory alloys. This article reviews about a hundred references on this topic, and presents around eighty actuators driven by shape memory alloys. A classification is made according to the type of rotation (continuous or non-continuous, single or reversible direction). Different factors are then discussed, such as the characteristics of the shape memory alloy elements, the heating and cooling system for the shape memory alloy, the control of the actuator, and the output torque and stroke which can be attained. This article provides the first review focused on rotary actuators triggered by shape memory alloys, highlighting the specificities and potentialities of such actuators for new applications in the future.