A Study on Optical Actuator Using Bimetal Element (1st Report, Analysis of Basic Characteristics and Linear Approximation Model)

A new type of optical actuator using bimetal element is presented, which consists of a bimorph structure of the high expansion coefficent material (Ni-Cr-Fe) and the low expansion coefficent material (36Ni-Fe). The fundamental characteristics of the bimetal were investigated experimentally and theoretically, which are of temperature and of displacement versus laser optical beam heating. The experimental setup consists of a laser diode as optical source, a thermocouple and a laser displacement sensor to measure temperature and displacement. The mathematical model of the actuator was also derived. In order to identify some parameters in the system, the finite element method (FEM) was adopted, which analyzes heat trasfer and thermal stress in the actuator. Comparing with the experimental results under various conditions, the simulation by FEM was carried out, and the good agreement with experimental results was obtained. Fainally, the application of linear approximate model with lst-order lag factor was examined.