Optimum Discrete Location of Shape Memory Alloy Wire for Enhanced Actuation of a Compliant Link

For discrete actuation with shape memory alloy (SMA) wires, the actuation moment can be controlled by changing the amount of wire offset. Increasing offset not only enhances the actuating moment, but also demands larger displacement capability of the actuator. In this paper, large deflection of a cantilever beam actuated by a SMA wire has been investigated. Both the theoretical and experimental results reveal the existence of an optimum offset maximizing the end deflection. The optimum offset depends on the flexural stiffness of the beam, SMA wire properties, and the input actuation level.