High-accuracy path-tracking by multi-axis coordination in CNC machines

A multi-axis coordinated control (MACC) system has been developed to achieve high-speed, high accuracy path-tracking in computerized numerically controlled (CNC) machines. Sharp changes in path speed or direction are kept within permitted acceleration levels by means of input command smoothing, which is achieved through the use of multi-axis coordination and a time-scaling method based on previewed velocity information. Since MACC is an online control method and can be modularized, it is easily incorporated into CNC machines. The results of both simulation and experimental testing of MACC on a CNC milling machine demonstrate its effectiveness and practical applicability. In high-speed milling, MACC has successfully reduced the path-tracking error to a greater degree than using the conventional post-interpolation filter method