Research on Error Modeling and Identification Technology of CNC Camshaft Grinder

Abstract Taking certain type of CNC camshaft grinders as the research object, through the analysis of its structure and movement to determine a total of 21 error parameters, a model describing the motion relations between adjacent body coordinate systems containing the error parameters was established. The machine movements were classified into two kinematic chains: the “bed-workpiece” and “bed-tool”. The topological structure of the machine tool was built and then the multi-body system theory was applied to model the errors of the machine tool. Body coordinate systems and motion reference coordinate systems were set up on each moving body and the corresponding transformation matrix was derived by joining the motion relation models between adjacent body coordinate systems. In order to achieve precision machining in the case of the existence of influential errors, a constraint equation Pw = Pt was put forward and solved. A mathematical model of the X-C axis linkage during camshaft grinding was proposed to work out the grinding point coordinates in the workpiece coordinate system and tool coordinate system. Three kinds of measurement methods were provided to identify 15 error parameters affecting the camshaft machining by using a cue instrument, which provides necessary conditions to research the machine tool error compensation.