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Precise position control using shape memory alloy wires

Donmez, Burcu
Ozkan, Bulent
Kadıoğlu, Fevzi Suat
Shape memory alloys (SMAs) are active metallic "smart" materials used as actuators and sensors in high technology smart systems [1]. The term shape memory refers to ability of certain materials to "remember" a shape, even after rather severe deformations: once deformed at low temperatures, these materials will stay deformed until heated, whereupon they will return to their original, pre-deformed "learned" shape [2]. This property can be used to generate motion and/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, modeling, simulation, and experimental efforts to precisely control the position of a Ni-Ti based shape memory alloy wire is presented. In this content three separate control strategies are tried and very good positioning accuracies are obtained.