Reducing the Power Consumption of a Shape Memory Alloy Wire Actuator Drive by Numerical Analysis and Experiment

The use of shape memory alloy (SMA) wire actuators for a moving body has some advantages over other conventional actuators because of the high specific power, small size, and simplicity of these actuators. However, the large power consumption of SMA wire actuators prevents its practical use. This paper shows how to optimize the input voltage of SMA wire actuators. First, a numerical actuator model is created from the measured data. Next, input voltage waves are optimized for three evaluation functions using multiobjective optimization: maximum input voltage, time-averaged actuators power consumption, and time-averaged bending moment (the output of actuator). The obtained numerical results show that a high maximum input voltage achieves efficient drive of SMA wire actuators. We also verified the tradeoff relations of the consumed power, maximum input voltage, and output from the SMA wire actuator under one condition of the multiobjective optimization. Experimental data also partially supported the tradeoff relations obtained by the multiobjective optimization and the numerical simulation.