关键词: G3连续, B样条, 曲率, 过渡, 拟合

Abstract: The corners on the toolpath lead to discontinuous tool motion of the machine tools during high-precision Computer Numerical Control（CNC）machining,especially in the finish machining process,resulting in varying cutting load which leaves tool deflection marks on the workpiece surface,hence reducing machining quality.To solve this problem,a G3 continuous tool path smoothing algorithm was proposed.The linear tool path was first divided into different non-fitting or fitting regions.Then,a corner transition model with optimized curvature was constructed based on B-spline for the non-fitting region to generate G3 continuous toolpath.For the toolpath in the fitting regions,the toolpath was fitted by B-spline and the G3 continuity of tool path at the connection points of consecutive non-fitting and the fitting regions was regarded as the fitting constraint.The proposed algorithm was demonstrated with simulations and experiments in following a tool path on a CNC machine tool.It was shown that the proposed G3 continuous tool path generation algorithm gave G3 continuous tool path,and reduced the tracking errors and contour errors,leading to better machining quality.

Key words: G3 continuous, B-spline, curvature, transition, fitting