According to ISO regulations, when describing the motion of a CNC machine tool, a right-handed rectangular coordinate system is used; the coordinate axis parallel to the main shaft is defined as the z axis, and the rotation coordinates around the x, y, and z axes are A, B, and C, respectively. The movement of each coordinate axis can be realized by the table or the movement of the tool, but the direction is defined by the movement direction of the tool relative to the workpiece. Usually five-axis linkage refers to the linear interpolation motion of any 5 coordinates among x, y, z, A, B, and C.