Abstract: Some problems are studied about shape memory alloy (SMA) spring used as a actuator in micro electromechanical systems. The thermal mechanical conversion process of SMA spring is modelled based on experiments. The major factors that affect on the action frequence of SMA spring are analysed and a way of improving its frequence characteristic is presented. With the concept of dimension sensitively, the effects of size minification on the driving characteristic of SMA spring are discussed.

Key words: Actuator, Micro electromechanical system, SMA