Abstract
So far, the researches on SMA (= shape memory alloy) thin film micro actuator for micro machine were reported about the metallurgical aspect, the sputter deposit process and the fabrication of devices with the SMA thin film. However the properties of SMA thin film as servo actuator has not been studied. On the other hand, the several characteristics of bulk SMA wire actuators to control it had been studied. In this paper, based on the same aspect as the bulk SMA wire actuator, the dynamical properties, the mathematical model and control of SMA thin film actuator were investigated experimentally. As the results, the summary is as follows. 1) The mathematical model of output force of SMA thin film actuator is expressed as the nonlinear and continuous function of temperature and strain. 2) The above function is found linearizable. Thus the linear mathematical model was obtained. 3) Tensile force could be controlled by the force sensor feedback system of the SMA thin film actuator.
