Micropositioning control using shape memory alloys

Shape memory alloys (SMA) are materials whose dimensions can be modified due to a temperature-dependent structural phase transition. This property can be used to generate motion or force in electromechanical devices and micro-machines. However, the accuracy of SMA actuators is severely limited by their highly nonlinear stimulus-response characteristics. In this work an experimental micropositioning device, based on a Ni-Ti alloy wire, is controlled. Several control strategies are experimented and position accuracies around one micron are achieved