Modelling and analysis of the dynamic response and self-sensing behaviour of CuAlNi /polyimide bimorph actuator.

A thin film shape memory alloy bimorph actuator developed by depositing CuAlNi shape memory alloy (SMA) on a curved Kapton polyimide sheet substrate can be used in position control without any biasing element or external sensor. Self-sensing capability makes SMA best suited for small size and low weight applications in the fields of medicine and aerospace. The dynamic behaviour of the bimorph actuator is analyzed with various inputs such as step, pulse and sine voltages, with and without load. The actuation of SMA bimorph exhibits nonlinear hysteresis. Also, the results show that some oscillations are present during heating when the bimorph is not loaded and these oscillations are absent/eliminated when under load. The SMA bimorph actuator's performances are approximated as the ARX441 model using the system identification technique. Further, the self-sensing model of the SMA bimorph actuator is developed using polyfit and ANN techniques and verified with the actual values. [ABSTRACT FROM AUTHOR]