DFA中零件对称度的自动识别算法  

Symmetry detection algorithm in design for assembly

作　　者：郑赟[1] 张林鍹[1] 肖田元[1] 

机构地区：[1]清华大学自动化系,北京100084

出　　处：《清华大学学报（自然科学版）》2008年第4期490-494,共5页Journal of Tsinghua University(Science and Technology)

基　　金：国家"八六三"高技术项目(863-511-030-003)

摘　　要：零件对称度是面向装配的设计(DFA)中评价装配性能的重要指标之一,对称度的自动识别能促进DFA与计算机辅助设计(CAD)系统的集成。针对已有识别算法效率较低的现状,给出了一种对称度自动识别的算法,该算法分为2个阶段,第一阶段通过旋转零件并比较其空间包容盒来计算对称度的范围,第二阶段利用射线追踪法进一步计算对称度的精确值,大部分非对称零件在第一阶段就可以结束计算,使得算法平均效率较高。基于CAD系统P ro/Engineer二次开发实现了该算法,并通过一组实例验证了算法的正确性和实用性。Part symmetry is one of the most important indices for evaluating assemblability in design for assembly （DFA） algorithms. Symmetry detection enables the integration of DFA and CAD but most current algorithms are not efficient. This paper presents a two-stage algorithm to automatically detect part symmetry. The first stage computes the symmetry boundary by comparing boundary boxes of rotated parts. The second stage uses ray-tracing to compute the precise symmetry. Most parts without symmetry are recognized in the first stage, making the algorithm more efficient. The algorithm has been implemented in Pro/Engineer, a leading CAD system. An example recognizing selected industrial parts shows that the algorithm is practical and effective.

关 键 词：计算机辅助设计(CAD) 面向装配的设计(DFA) 对称度 空间包容盒 射线追踪 

分 类 号：TP39[自动化与计算机技术—计算机应用技术]