研磨ロボット用光学的表面粗さセンサの研究 １ Ｔｏｒｒａｎｃｅ‐Ｓｐａｒｒｏｗモデルに基づく表面粗さの測定原理

Abstract

This paper proposes a new optical method for measuring roughness of ground surfaces, especially for a pol-ishing robot. In-process measurement. of surface roughness is an important factor in automatic precise polishing. The roughness of such metallic surfaces can be measured exactly by a stylus roughness meter. However, for the reasons of vibration arising during grinding and of a long time necessary for the measurement, the stylus roughness meter is not applicable to in-process measurement. An optical, non-contact measurement is well suited to harsh environment in grinding processes. In this paper, a halogen light source is used and its reflection from the surface to be measured is collected by a CCD camera. The gathered image data are processed by a newly proposed procedure. Based on the Torrance-Sparrow model, this procedure theoretically converts the data of the reflected lightt into surface roughness represented in Rrms (roughness in root mean square). The correlation between the image data and the roughness of the surface is not sensitive to the brightness of the light source as well as the material composing the surface.