Development of 5-degree-of-freedom displacement measuring device using PSD

Abstract

For advanced satellite missions, the requirement of larger and more accurate space structures has become severer. However, it is becoming difficult to meet the demand for highly accurate only by high-accuracy manufacturing and assembly using materials with excellent shape stability. Therefore research on shape control of space structures has been actively conducted. In order to control the shape, the amount of deformation of structure should be measure accurately. In past research, there are few studies about the measurement system for multiple degrees of freedom displacements. In this study, we developed a measuring device using laser and PSDs for 5-Degree-Of-Freedom displacements (two translational DOFs and three rotational DOFs). The measuring device proposed in this study consists of three PSDs, two retroreflectors, and one flat mirror. The displacement given on the stage and the displacement measured by the 5 DOFs measuring device matched with a sufficiently small error. We also evaluated crosstalk using the ratio of the measured displacement to the maximum range of motion. Crosstalk was within 3% for translational displacement and within 5% for rotational displacement. As a result, it is shown that the 5 DOFs measurement device using PSD is useful.