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Precise position control using shape memory alloy wires

2010-01-01
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.