A New Assembly Relationship Model Supporting Assembly Reorganization for Assembly Planning

摘要

Assembly planning becomes more difficult due to the increasing complexity of products. So complex product is usually decomposed recursively into various level subassemblies and comes into being a hierarchical structure during assembly planning process. Reorganizing directly design hierarchical structure tree established at design stage to create assembly hierarchical structure tree under virtual assembly environment, by which realized the subassembly repartition that meets various requirements of assembly manufacturing, is an efficient method of rapidly assembly planning. However, the existing CAD assembly model, especially assembly relationship model,is unable to support efficiently the assembly reorganization.In this paper, the assembly relationship information,which includes mating relationship, geometry constrain,connecting relationship and motion relationship, is firstly introduced. On the basis of analysing the modifying influence to assembly relationship information by assembly reorganization, assembly relationship element (ARE) model is proposed which associates assembly relationship model with hierarchical structure model. The changing rule, of fulfilling attribute and exhibiting attribute of ARE during assembly reorganization is proposed. The method of storing ARE in assembly model is also presented. Three characteristics of assembly relationship model based on ARE are finally summarized that can insure the consistency, integrality and correctness of whole assembly model during rapidly assembly planning.