Abstract
The actuators using shape memory alloy can work as an actuator to control or retain positioning without using sensor device. In order to utilize the shape memory effect, the bias force such as coil spring and constant load is required to deform the shape memory alloy in martensitic phase. In this work, the effect of a bias load on the positioning characteristics by resistance feedback control is investigated. The produced actuator is heated by electric current and it can control the position using a constant mass and a bias spring as a bias load. The Ti-Ni-Cu alloy wire is used as an actuator element. The positioning characteristics such as settling velocity, positional error, and position accuracy are discussed in relation to the bias load. The results show that the settling velocity at heating decreases and the settling velocity at cooling increases with increasing in the bias load. Furthermore, the positional error at heating is very small and the positioning control against the desired position during heating can be controlled accurately.
