Abstract: During machining the high accuracy non-circular part, normally the trajectory of non-circular part profile is generated, and then the fast response linear servo motor drive the cutting tool to do reciprocating moving, and control the cutting tool synchronously with the spindle. The control accuracy of the non-circular part trajectory is critical to affect the non-circular part CNC machining. Based on the periodic features of non-circular profile trajectory, the control algorithm which is hybrid control of PID and iterative learning control has been effectively developed for non-circular profile generation. Because the load disturbance can negatively affect the control accuracy, so the disturbance observer is integrated to the control algorithm. The final motion accuracy of linear actuator has been improved, and the machining accuracy of the non-circular turning is improved.

Key words: iterative learning control;digital pid control;disturbance observer;non-circular machining;high speed response linear servo motor