Phase Transformation Modeling and Robust Adaptive Control of Shape Memory Alloy Actuators

Shape Memory Alloys (SMAs) show special properties that make them a suitable choice for industrial applications in many branches of engineering. SMAs can effectively change their shape and provide actuation by reinstating their memorized geometry. Different models are developed for the thermomechanical behavior of SMAs which are consisting of two main parts: a constitutive part and a phase transformation kinetics part. Several methods of controlling SMA actuators have been investigated; in this work, an improvement applies on Lagoudas’s assumptions in phase transformation of SMAs and a new model is presented. Result of this model is well-matched with the experimental results. After that robust adaptive control is applied on a single degree of freedom robot with actuation of SMAs. For this reason initial nonlinear system is linearized using feedback linearization; then robust adaptive control is utilized on the system. Once outage power happen SMA actuator need some time to be cooled, as a result, more settling time is required in comparison with other actuators; and this fact is clearly appeared in final results. Lastly final results show that the system is asymptotic stable under robust adaptive control.