Shape memory alloy actuator with simple adaptive control

This paper proposes a small shape memory alloy actuator unit and its control algorithm. Since the unit contains a part to sense its displacement and stiffness, no external sensors are needed. SMA deformation is driven by thermal dynamics which can be significantly effected by surrounding environment. In order to attenuate this effect, a robust and simple control algorithm, simple adaptive control is adopted. The proposed method was evaluated by the developed actuator unit. Experimental results showed that the stiffness was well controlled and the position could be controlled to converge the desired displacement