摘要
针对现实机械装配中零部件存在公差信息的事实,给出了基于公差约束的虚拟装配方法:首先,构建了虚拟零部件的层次信息表达;其次,提出了基于体分解的空间包围体压缩方法,对零部件原始的包围体进行切分压缩,并由此构建平衡二叉树,建立了与二叉树叶节点对应的零部件碰撞模型,对于包围体切分中出现的冗余面片采取了冗余面片索引技术;第三,给出了虚拟环境中静态零部件周边空间环境的切分方法,采用分离轴方法对位于环境剖分立方体内的碰撞模型进行碰撞检测;第四,给出了零部件三角面片碰撞穿透深度的计算方法,并依据此深度值与零部件间公差范围进行比对,判断碰撞是否在公差范围内;第五,以轴孔装配为例,给出了零部件在虚拟空间中装配意图的判断方法及装配的约束方程表达;最后,通过仿真实验给出了零部件之间的装配过程。实验结果表明,该方法可以提高零部件的装配效率,更好地仿真装配过程。
For the fact that the mechanical components and parts have the tolerance information, an assembly method based on tolerance constraint in virtual assembly was proposed in this paper. Firstly, the hierarchical information models of the components and parts were constructed. Secondly, the com- pressed method of space Bounding Volume （BV） based on volume decomposition was proposed to seg- ment and compress the original BV, the Balanced Binary Tree （BBT） was constructed according to the result of the segmenting and compressing the BV, the collision model of the components and parts was constructed corresponding to the leaves of the constructed BBT, and the method of indexing redundant triangle patches was given to solve the problem of the redundant patches created in the process of the BV segmentation. Thirdly, the space environment segmenting method nearby the static components and parts in virtual environment was illustrated and separating axis was used in the segmented virtual envi- ronment cube to judge whether the collision occurs between the collision models of the components and parts. Fourthly, the method of calculating the collision penetration depth of triangle patches was men- tioned and by contrasting the depth value calculated with the part tolerance range, it was confirmed whether the collision is in the tolerance range. Fifthly, as the hole-axis assembly an example, the method of judging assembly intention and the assembly constraint formulas were indicated. Finally, the assembly process of components and parts was shown by assembly simulation. The simulation result indi- cates that this method can increase the assembly efficiency and enhance assembly simulation performance.
出处
《计算机工程与科学》
CSCD
北大核心
2013年第6期162-173,共12页
Computer Engineering & Science
基金
国家自然科学基金资助项目(61074053)
交通运输部交通应用基础研究项目(2011-329-225-390)
中央高校基本科研业务费资助项目(DC120101083)
关键词
虚拟装配
碰撞检测
包围体
冗余面片
公差
约束
virtual assembly
collision detection
bounding volume
redundant patch
tolerance
constraint
