Including assembly process information (API) in product assembly model for better assembly of product

Assembly process information (API) includes information about assembly fixture, assembly tools, assembly operation, and so on. Up to now, lack of adequate API in assembly model has, in our opinion, brought to the actual assembly many problems such as: fixing difficulty, inadequate space of assembly operation, and bad access to assembly environment for assembly-cells and API. Then assembly planning has to do poorly done work over again. This paper presents an assembly model integrating adequate API. The basic idea of the approach is to express API in assembly model by building prior relationship and constraint relationship between assembly-cells and API. We analyze and define prior relationship between assembly-cells and API when assembly-cells and API come into and come out from assembly environment. Assembly model integrating API is built by connected-graph model based on directed graph and undirected graph. Firstly, the directed graph represents the prior relationship between assembly-cells and API when assembly-cells and API come into and come out from assembly environment. Secondly, the undirected graph represents assembly relationship between assembly-cells and API. Thirdly, a connected-graph model is used to integrate the directed graph and the undirected graph. So an assembly model integrating API appears. Then this model is expressed using adjacency matrix. The assembly model integrating API is propitious to expressing experiences of assembly process and to planning assembly sequence of product. We applied our approach successfully to planning assembly process of a certain aircraft wing, whose assembly went on quit smoothly.