A Curvature-Continuous Transition Method with Axis High-Order Kinematic Limitations along Linear Segments

摘要

Linear toolpath is the most typical codes in practical Computer Numerical Control (CNC) systems and the kinematic parameters in terms of axis acceleration and jerk are difficult to limited in high-speed and high-precision machining. Various path-smoothing approaches are proposed to cope with that drawback, while the axis jerk is still not limited in most researches. In order to improve the machining quality further, corner feedrate limitations with axis jerk are deduced in theory. Similarly to the curvature extreme, the curvature derivative extreme should also become the critical points and it would determine the distribution of axis jerk. With the typical cubic Bspline transition method, the transition model is optimized to obtain smaller curvature derivative extreme, which leads to larger corner feedrate as well as higher machining efficiency. Thereby, a new motion planning algorithm is presented with jerk limited acceleration profile to adapt the changes of critical points. Finally, simulation and experiment comparisons of three already existing approaches are presented to show obvious improvements in both cycle time and contouring performance.