三维工序模型加工特征环境匹配

Study on the Environmental Matching of Machining Feature for 3D Process Model

针对传统的基于"相似零件结构有相似工艺"准则的知识检索方法所造成的知识重用精度低等缺点,提出了一种基于"相似加工特征环境有相似工艺"的三维机加工艺知识复用方法。首先,利用属性邻接图建立工序模型的数学表达,使用改进的子图同构匹配方法进行加工特征提取。然后使用加工特征邻接图将提取出的加工特征进行重构。通过定义裁剪规则,得到基于特征的加工特征环境结构。将特征的环境结构作为输入条件与工序模型进行相似匹配,匹配参数包括特征类型、依附面类型以及特征间拓扑关系等信息,使加工工艺知识得以复用。实例验证表明,该方法有效地匹配了相似的加工特征环境并通过加工特征环境的检索,实现相似工艺的匹配。

Aiming to the criteria of knowledge retrieval methods resulting in low precision of knowledge reuse via the traditional ' similar parts structure with similar process',3D machining process knowledge reuse methods is proposed based on the ' similar environmental characteristics with similar process'. Firstly,the AAG( Attribution Adjacency Graph) process model is established a mathematical expression with a modified subgraph isomorphism matching method for processing feature extraction. Secondly,the extracted features is reconstructed with the machining feature adjacency graph processing. Thirdly,the feature-based machining feature environments is gotten by defining rules. The matching parameters including the feature type,attachment surface types and topological relations between features and other information,the machining process knowledge can be reused by inputing the machining feature environment for similarity matching into the process models,. Examples show that the present method can effectively match a similar machining feature environment and search the environment so as to match the similar process.