Tracking control of shape memory alloy (SMA) actuators is essential in many applications such as vibration isolation. Due to the hysteresis, an inherent nonlinear phenomenon associated with SMAs, control design based on linear methods has proven inadequate for tracking control of these actuators. In this paper, a novel tracking controller employing a nonlinear robust compensator is proposed for SMA actuators. The control design uses the sliding-mode approach and requires no detailed information of the SMA model. To test the effectiveness of the proposed controller, a single SMA wire test stand is built. A titanium-nickel SMA wire stretched by a bias spring is used as an actuator for tracking control. Experimental results show that the SMA wire actuator under the robust control can precisely follow a sinusoidal path and the effectiveness of the proposed control strategy is demonstrated.

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