Nonlinear error analysis of convex surface grinding in RTCP mode

When linear interpolation is carried out on the micro straight line segment, the actual motion synthesized by each motion axis of the machine tool will deviate from the programmed trajectory, resulting in the rotation error of the cutter shaft. The reason of error in five axis NC machining of RTCP system is analyzed. The mathematical model of nonlinear error formation process is established. The calculation formula of nonlinear error is simplified. It is pointed out that the nonlinear error is related to the length of the interpolation line segment and the angle between the normal vectors of the convex surface of the workpiece at the tool contact at both ends of the interpolation line. Finally, it is found that the error easily ignored in RTCP mode: the nonlinear error produced by grinding convex workpiece with five axis CNC machine tool is less than the discrete error when the tool path curve is discretized into a straight line.