Research On Knowledge-Based Product Conceptual Design In Virtual Enterprise

In the dynamic and changing market environment,manufacture enterprises have to conduct product innovation,and adopt the mode of agile manufacture to build virtual enterprises for solving Time-Quality-Cost-Service (TQCS) problems. Research on knowledge-based conceptual design in virtual enterprises is very meaningful for the above aims. In virtual enterprises,the knowledge needed by product conceptual design is distributed among its members. Therefore it is of vital importance to organize,capture,and integrate the knowledge for enhancing conceptual design evolution and decision-making. The dissertation has systematically researched on problem solving in conceptual design in virtual enterprises,conceptual design information modeling,acquisition of conceptual design knowledge,capturing and integration of the knowledge for conceptual design decision. The main contents and achievements are articulated as follows:(1) Problem solving in conceptual design in virtual enterprisesThe features and cause of ill structure of conceptual design problem have been analyzed. The representation of design state,including product specification and FBS framework,the methods and features of design decision,and problem solving based on knowledge in conceptual design stage are studied. Based on the above work,it is pointed out that the cause of ill structure of design problem lies in the absence of knowledge for decision-making in the initial stage of design,and that capturing the knowledge for conceptual design decision is an effective method for reducing the degree of structural illness. Concurrent conceptual design method has also been studied. On the basis of process modeling of conceptual design in virtual enterprises,the types,features,forms,and distributed situations of the knowledge needed by the process are analyzed. Finally,the architecture of knowledge-based conceptual design system in virtual enterprises is proposed.(2) Conceptual design information modelingThe content and representation of non-geometric and geometric information in conceptual design information have been studied. Through building functional,behavioral,and structural model,formal representation of function,behavior,and structure in FBS framework is realized. The geometric model for computer-aided industrial design,which supports the method of Top-Down,is constructed. It can record the history of geometric modeling and provide the mechanism of controlling the granularity of geometric information. Finally,a conceptual design information model is built,which,being fully formalized,record the history of conceptual design and support its reuse.(3) Conceptual design reuse in virtual enterprisesThe requirements of conceptual design reuse in virtual enterprise have been analyzed. Then the methodology of building design reuse system based on PDM system is put forward. The integration of conceptual design information model and metadata of PDM is also researched,on the basis of which,the framework of conceptual design reuse that has multi-granularity is built. At the same time,the algorithms of matching design intent and retrieving conceptual design reuse information are presented. Finally,the architecture of web service-based design reuse system being interoperable and loose coupling is presented. And the conceptual design markup language is built.(4) Ontology-based knowledge capturingThe basic theory of ontology has been researched,which includes the definitions of ontology and related concepts,structure of ontology,and representation of different parts of ontology. Then enterprise ontology and product ontology in it are researched;and the method of building product ontology on the basis of STEP is provided. On the basis of ontology-based knowledge representation,the methodology of ontology-based knowledge capturing is put forward for the first time. Its principle and application on capturing the knowledge for conceptual design decision are also discussed.(5) Capturing and integration of the knowledge for conceptual design decision...