Abstract: Abstract： A mathematical model was established and analysis of geometric deviation was conducted based on spherical grinder to study the influence of the grinder on sphericity error. The grain trajectory considering geometric deviation was studied and the relevant model was built. The grossed ratio of grinding marks was defined as a statistic feature to evaluate the geometric deviation. A novel vision detectionbased method was proposed to estimate the sphericity error based on the crossed ratio of grinding marks. The proposed method enables insitu evaluation of sphericity error and is meaningful for further insitu sphericity error compensation.

Key words: spherical grinding, sphericity error, grinding marks, geometric deviation