数控系统中指令点纠正平滑处理算法

Command Point Correction and Smooth Tool Path Generation Method in CNC System

针对数控系统中小线段平滑加工的需求,在分析现有小线段平滑加工算法不足的基础上,提出一种指令点纠正平滑处理算法.该算法根据小线段间的几何关系将数控程序表示的刀具路径划分为连续区域和非连续区域.对非连续区域,通过圆弧纠正方法,减少刀具路径生成过程中产生的异常指令点.针对处理后刀具路径上的连续区域,提出一种三次样条指令点纠正方法,对指令点的位置进行进一步的修正.在满足加工精度的条件下,基于NURBS曲线,通过对修正后的指令点进行拟合,对刀具路径进行平滑处理.仿真结果表明,该算法可以对刀具路径进行有效纠正,扩大拟合区域包含的刀具路径长度,并提高刀具路径的平滑性.

Based on the analysis of the existing methods used to generate smooth tool path,this paper proposes a command point correction and smooth tool path generation method of short line segments,aimed to generate smooth tool path.Firstly,the tool path is divided into fitting region and nonfitting region based on the geometrical feature of short line segments.Secondly,a command point correction method based on circle is proposed to reduce the abnormal instruction points.For the fitting region on the smoothed tool path,a command point correction method based on the cubic spline is proposed to make the position of the command points smoother.Thirdly,the tool path is fitted into NURBS splines under the machining accuracy to generate smooth tool path.Simulation results demonstrate that the algorithm proposed in this paper enlarges the area of the fitting region and improve the smoothness of the tool path through the proposed command correction method.