Abnormal Control and Trajectory Optimization in CNC System

In CNC machining, the motion controller executes in real-time to generate trajectory points. when abnormal situations occur, the controller changes its execution to deal with it, protect machine components and machining parts. In this paper, a feed rate reset method which across multiple segments is proposed and integrated in micro-line trajectory planning routine. In trajectory planning process, to make sure CNC machine not exceed its mechanical limits, look-ahead method is applied to readjust corner velocity. To optimize trajectory, two corner transition methods are chosen based on machining time and the smoothness of the velocity profile, and the controller intelligently choose one of them based on the current machining situation. These methods are tested in simulation environment and actual machining.