Abstract
In order to realize a high-speed, accurate and compact positioning system by a parallel mechanism, it is necessary to use ball joints each having three degrees of freedom. Such a ball joint is requested to have highly precise spherical surface inside the housing, in which a shank-connected "sun ball" in center and "satellite balls" around it are all put away. In the present study, we focused our attention to obtain a genuine spherical surface inside the housing and to control the position of center of the sphere precisely. We examined various processes by using a self-made polishing machine for the exclusive use. Through those examinations we got good results, and here we report them besides with a measuring method of a spherical surface.
