Oriented bounding box and octree based global interference detection in 5-axis machining of free-form surfaces
Oriented bounding box and octree based global interference detection in 5-axis machining of free-form surfaces
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DOI：
10.1016/s0010-4485(03)00109-x
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发表时间：
2004-11-01
影响因子：
4.3
通讯作者：
Poo, AN
中科院分区：
文献类型：
--
作者：
Ding, S;Mannan, MA;Poo, AN
全局干涉检测是自由曲面五轴数控加工中的一个关键问题。基于虚拟现实中用于检测三维物体之间空间碰撞的层次有向包围盒（OBB），本文开发了一种新的全局干涉检测方法。在该方法中，为了简化五轴加工中刀具位置和方向更新的计算过程，刀具和刀架采用层次有向包围盒结构建模，而工件表面则用八叉树近似表示。利用分离轴定理在刀具的有向包围盒和表面八叉树的灰色八分面体之间进行干涉检测。借助八叉树的层次结构，如果在一个八分面体中发现干涉，则进一步处理其子八分面体以定位确切的碰撞叶节点，并使用常规矢量计算方法对这些叶节点中包含的离散化表面点进行精确干涉检测；如果未检测到干涉，则所有子八分面体都被视为无干涉，不再进一步处理。同时，借助刀具有向包围盒的层次结构，如果八分面体与层次结构第一层中的有向包围盒之间发生干涉，则进一步测试第二层中的子有向包围盒。否则，可以确定刀具与八分面体之间无干涉。（C）2003年由爱思唯尔有限公司出版。
Global interference detection is a critical problem in 5-axis NC machining of free-form surfaces. Based on the hierarchical oriented bounding box (OBB) which is used in virtual reality to detect spatial collisions between 3D objects, a new global interference detection method is developed in this paper. In this method, in order to simplify the computation process of updating tool positions and orientations in 5-axis machining, the cutter and cutter holder are modeled by a hierarchical OBB structure, whereas the workpiece surfaces are approximated by an octree. Interference detection is conducted between the tool OBBs and the gray octants of the surface octree with the separating axis theorem. With the hierarchical structure of octree, if interference is found in one octant, its sub-octants are further processed to locate the exact colliding leaf nodes and the discretized surface points contained in these leaf nodes are tested with a conventional vector calculation method for exact interference detection; if no interference is detected, all the sub-octants are then considered as interference free and are not processed further. Meanwhile, with the hierarchical structure of the tool OBBs, should interference occur between octants and the OBBs in the first level of the hierarchical structure, the sub-OBBs in the second level would be further tested. Otherwise it could be determined with certainty that there is no interference between the tool and the octant. (C) 2003 Published by Elsevier Ltd.