一种有向投影的测量数据刀具轨迹生成技术

摘要

To improve the low accuracy and efficiency in reverse engineering, a new approach is proposed to generate tool path from the measured data by direct projection. Following the principle of projection algorithm, an iterative process is defined to continuously update the neighboring points, then an approximate plane fitted with least squares method is created for calculating the intersection of the object and the projection ray. The procedure is repeated until the required accuracy is met. The tool path generation technique based on the reference surfaces is discussed. A reference surface is created for the input point cloud, the sampling points on tool paths are defined and projected on the offset of the point cloud, and cubic B-spline is chosen to interpolate the projecting points to generate a tool path. The experiments show that the proposed strategy avoids the surface reconstruction and improves the effectiveness and accuracy with stable computation and simple operation.%为解决实物反求工程中零件加工精度和效率低的问题,提出了一种适合于测量数据的有向投影算法,并用于刀具轨迹的生成.按照投影原理,通过一个迭代过程不断地更新交点附近的邻近点集,再利用最小二乘法建立近似平面来计算其与投影线的交点,直至达到要求的误差精度.研究了基于参考曲面的刀具轨迹生成机理,先构造参考面并确定采样点,然后将其沿着投影方向映射到偏置点云上,再采用三次B样条曲线插值法生成刀具轨迹.实验表明,该方法可以有效地避免曲面重建,并且计算稳定、操作简单,从而提高了实物反求的效率和精度.