An SMA actuator controlled by Peltier effect

抄録

Microtechnologies and microsystems engineering use new active materials for microactuators and microsensors. In this field, Shape Memory Alloys (SMA) are good candidates for microactuation. They can actuate microrobots and are able to provide very important forces, but have low dynamic response, especially for cooling. Joule effect is an easy and classical way to heat the SMA actuators, but cooling is not so easy. Dynamic response of the actuator depends on cooling capabilities. This paper describes a reversible way for heating and cooling SMA microactuators, based on the Peltier effect. Using Peltier effect, a positive or a negative electrical current is able to absorb or produce heat in the SMA actuator. The integrated SMA microactuator presented here in the millimeter size. It consists of a thin blade of SMA working in flexion and placed in junction with a material with high thermoelectric features. This material is Bi₂ Te₃, i.e. bismuth telluride, N an P doped. As far as we know, it is one of the first investigations with a real measurement of the motion of the SMA actuator using integrated thermoelectric junctions. Using this system, we are able to control the temperature of the SMA blade in a range of -10°C to 90°C. Some experimental results are given.