Feedrate scheduling and jerk control algorithm for high-speed CNC machining

摘要

High-speed CNC machining usually slows down around corners and vibrates so much because of limits on processing large amount of consecutive small line blocks with high speed and inability changing directions fast enough. Aiming at adjusting the feedrate automatically and providing smoother acceleration to achieve maximum productivity, this research presents a feedrate scheduling and jerk control interpolation algorithm to seek the optimal feedrate by evaluating the tool path ahead. After generating a smooth path within error allowance by B-spline fitting algorithm, we calculate the safe, highest, continuous linear velocity while simultaneously accommodating the machine's Acceleration/Deceleration (Ace/Dec) limits. Smooth jerk motion is obtained by modulating the acceleration profiles along the tool path. A look-ahead interpolation scheme is also presented for the purpose of fast controls. Simulation results indicate that the proposed adaptive algorithm speeds feedrates, limits distortion to the programmed path, maintains high speed without sacrificing accuracy while going around corners.