Abstract: Aiming at the problem that the dynamic response of the axes of the CNC machine feed servo system was inconsistent, which led to the reduction of part processing accuracy, the motion control of the feed servo system of CNC machine tool was studied. The control method that combined iterative learning control and cross-coupling structure was proposed, the iterative learning controller of the single-axis position ring of the in-service servo system was designed to suppress the single-axis following error, and the multi-axis variable gain cross-coupling learning controller was designed to suppress the multi-axis contour error. By using the simulation model built in MATLAB/SIMULINK environment, the trajectory of the three-leaf rose curve was tracked and verified, and the designed controller was comparing with other control methods. The results indicate that the maximum contour error and average contour error of the tracked curve are reduced comparing with other control methods, which proves that the single-axis and multi-axis motion controllers can reduce the contour error and improve the precision of part processing.

Key words: contour control; contour error; cross-coupling control; iterative learning