数控加工中连续微线段轨迹的B样条曲线拟合

为解决数控系统进行连续微线段加工时加减速频繁、运行速度缓慢、加工路径不连续等问题,提出了最小二乘3次B样条曲线逼近拟合算法,采用该算法实现对连续微线段的逼近.文中通过分析连续微线段加工路径的几何特性,提出了采用圆弧近似法计算的弓高误差准则,并选择满足条件的可拟合点集,将拟合的曲线相对于原有路径的偏离误差控制在要求范围内.实例仿真结果表明,该算法可在保证拟合精度的同时有效地拟合连续微直线段.

B-Spline Curve Fitting of Consecutive Micro-Segment Trajectory in NC Machining

In order to overcome the frequent acceleration and deceleration,low machining feedrate and disconti-nuous machining path in the traditional consecutive micro-segment machining process,an algorithm of cubic B-spline curve fitting based on the least square method is proposed to approximate the consecutive micro-segment to a B-spline curve.By analyzing the geometric characteristics of the machining path of the consecutive micro-segment,a chord error constraint based on the arc approximation is presented to pick out appropriate points and keep the deviation of the fitted curve from the original path in a required range.Simulated results indicate that the proposed algorithm can effectively fit consecutive micro-segments into B-spline curves without reducing the precision.