Precision Positioning with Shape-Memory-Alloy Actuators

Abstract

The primary purpose of this study is to improve the positioning performance of shape-memory-alloy (SMA) actuators. In order to achieve this goal, the system nonlinearity was reduced with the inversion of a nonlinear model.  The system could then be approximated with a linear model. It is easy to construct the corresponding model-reference-adaptive-system (MRAS) based on this linear model. Experimental results show that the MRAS is robust with respect to external disturbances and improves the positioning performance. In addition, with the proposed control scheme, the simulation results will closely match experimental results, which is useful to predict the system performance at the controller-design stage.