等离子弧表面处理中的NURBS曲线拟合及轨迹点算法

针对等离子弧表面处理技术的特点,提出了一种基于NURBS曲线对复杂工件表面曲线进行拟合,进而利用拟合曲线选取合适轨迹点的算法。根据等离子弧发生器行走轨迹精度的要求,改进反求控制点,在NURBS曲线最大误差处增加型值点,且利用曲率积分找到曲线上的关键点,再将这些点作适当平移作为等离子弧发生器运行的轨迹点,提高等离子弧表面处理异形工件的质量。该算法能有效简化曲线拟合和求等离子弧发生器轨迹点的计算过程。

NURBS Curve Fitting and Track Point Algorithm in Plasma Arc Surface Treatment

This paper proposes an algorithm based on NURBS curve to fit the surface curve of complex workpieces and then use the fitting curve to select suitable track points.According to the accuracy requirements of the plasma arc generator walking track,the algorithm of calculating control points is improved via increasing the value point at the maximum error of the NURBS curve.The curvature integral is used to find the key points on the curve,and then these key points are properly moved as the track points of the plasma arc generator to improve the quality of the plasma arc surface treatment of the shaped workpiece.