Abstract: Aiming at the complex structure of rib feature in aircraft structural parts and recognition difficulty of intersecting rib feature,a new feature recognition method based on Vertex Attributed Adjacency Graph (VAAG) was put forward.In VAAG,nodes represent edge was represented as the node and the adjacencies among theses edges were as the arcs.Through constructing the VAAG for the seed face of rib feature,the edge information could be handled and expressed to make up the insufficient of traditional attributed adjacency graph.Extreme point was extracted to represent the rib feature boundary and the intersection of rib feature ends by analyzing the node type and connected relation.Division node was constructed for the representation of rib features top face regions to reduce the rotation speed in actual processing.Virtual links were added automatically and VAAG of rib feature's seed face was decomposed to obtain the optimal identifiable result of intersecting rib features.Based on the above research,an automatic numerical control programming system of rib feature was developed,which had been successfully applied in a large aviation manufacturing enterprise.

Key words: aircraft structural parts, feature recognition, rib feature, vertex attributed adjacency graph, extreme point, division node, virtual link

摘要： 针对飞机结构件中筋特征结构复杂、相交筋特征识别困难的问题,提出一种基于属性边点图的筋特征自动识别方法。属性边点图以边为节点、以边与边之间的连接关系为弧。通过构造特征种子面的属性边点图,可以有效表示和处理筋特征中的边信息,弥补了传统属性面边图的不足。用端点表示筋特征两端的边界,通过端点类型及连接关系的分析,确定筋特征两端的相交情况;用分割节点来表示筋特征顶面的融合区域,以减少实际加工时的转角减速为优化目标,在分割节点处自动添加虚链,并对筋特征种子面的属性边点图进行分解,得到优化的相交筋特征识别结果。基于以上研究开发的筋特征自动数控编程系统已在某大型航空制造企业中得到良好的应用。

关键词: 飞机结构件, 特征识别, 筋特征, 属性边点图, 端点, 分割节点, 虚链