구면 반사체를 이용한 3 자유도 변위 측정 기법

Abstract

A precision displacement measuring system to detect the three-DOF translational motions of precision positioning devices is proposed. The optical system is composed of two diode laser sources and two quadratic PSDs. And, it is adapted for detecting the position of the spherical refelctor which is usually mounted on the flatform of positioning devices. Each of the laser beams from diode-laser sources is reflected at the highly reflective surface of the sphere. Hence, the movement of the sphere changes reflected beam's direction which can be detected by the PSDs. The relationships between the output values of the PSDs and the three-DOF translational motions of the sphere were defined. And, the performance of the proposed measurement system was evaluated by the computer simulation: sensitivity, measuring range, and optical measurement error. The results show that the proposed measuring method is very useful for the measurement of the precision displacement of three-DOF micro motions.