| 引用本文: | 王兴波,李圣怡.平面 NURBS 曲线的椭圆弧自适应逼近.[J].国防科技大学学报,2000,22(4):23-26.[点击复制] |
| WANG Xingbo,LI Shengyi.Auto-adaptable Approximation of Planar NURBS Curve with Ellipse Arc[J].Journal of National University of Defense Technology,2000,22(4):23-26[点击复制] |
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| 平面 NURBS 曲线的椭圆弧自适应逼近 |
| 王兴波, 李圣怡 |
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(国防科技大学 机电工程与自动化学院, 湖南 长沙 410073)
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| 摘要: |
| 给出了用椭圆弧及双椭圆弧自适应逼近平面NURBS曲线的算法。算法所得到的椭圆样条能够G1连续, 双椭圆样条还能够保形。与现行的圆弧逼近算法相比, 本算法不需要求解非线性方程组, 而是由给定的插补误差自动计算参数增量, 得到椭圆曲线的特征点, 还可以将误差控制在预期的范围之内; 与现行的直线插补方法相比, 不需要额外的时间和空间, 也适用于CNC环境。本算法在腔体加工、二维轮廓加工等方面有特别的实用价值。 |
| 关键词: NC加工 NURBS 曲线 曲线逼近 插补 |
| DOI： |
| 投稿日期：1999-12-24 |
| 基金项目:湖南省自然科学基金资助项目(99YJJ2005); 国家杰出青年基金资助项目(59725511) |
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| Auto-adaptable Approximation of Planar NURBS Curve with Ellipse Arc |
| WANG Xingbo, LI Shengyi |
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(College of Mechatronics Engineering and Automation, National Univ. of Defense Technology, Changsha 410073, China)
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| Abstract: |
| An algorithm to approximate a planar NURBS curve by ellipse-arc and bi-ellipse-arc is presented. The piecewise ellipse-arc spline calculated by this algorithm is G1 continuous, and shape preserving. Compared with the present arc-approximation, this algorithm does not need equation-solving, and enable an automatic choice of parameter increment responding to the given interpolation tolerance in calculation of the character points of ellipse-arc. The algorithm also has advantage in approximation error control, which can control the approximation error to an expected one. Compared with present line-approximation mode, this algorithm, which needs no extra time and space in calculation, is applicable to CNC environment. The algorithm is specially valuable in cavity and contour machining. |
| Keywords: NC machining NURBS curve approximation to a curve curve interpolation |
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