Study On Product Functional Design Based On Event Model And Its Applications

The conceptual design is one of the most active and creative stages in the productdesign process. The function is the main processing object of the conceptual design. Theabstraction, representation, decomposition and reasoning of function are the core issuesof the conceptual design. In recent years, as a kind of knowledge representation methodwith broad application prospects, the event has become one of the hot spots of theknowledge processing fields such as artificial intelligence. From the perspective of theevent, this paper studied the correlative issues of the functional design based on theevent model. The main research work can be described as follows.1. Based on the cognitive thinking of the product composition, an event cognitivestyle of the product was proposed. According to the analysis of the concrete entitativeand abstract functional composition of product, from the view of point of cognition, thecomposite problem of the product with the event was explored. An event cognitive stylethat used the event as the basic compositive unit was proposed. The products can beessentially seen as the systems that ensure the events reflecting the product functionsoccur controlled and orderly. This cognitive style is in line with people’s thinking habits,and is convenient for people to understand and use.2. In order to provide the unified description way for the event which acts as thebasic compositive unit of product, the mathematical representation model of the eventwas built. In the event representation model, the ontology is defined based on the theoryof propositional logic to describe the connotation of the event and the variant is definedbased on the theory of domain relational calculus and set theory to express the variationrange of the event, and the variant is alterable part of the event under the constraints ofthe ontology. It can successfully combine the ontology and variant together to representthe whole event. Based on the event representation model, an event operation modelwas built to describe the event operations such as selection, projection, instantiation,connection and decomposition etc. The event representation model and the eventoperation model constitute the event model. In the event model, the ontology of theevent gives the basis of event change, the variant delineates the change range of theevent, and the operations of event realize the change methods of the event. It lays thefoundation for the research about product functional design and design diversity.3. Depending on the requirement that the functional representation should expressthe connotation and the extension of function simultaneously, a functionalrepresentation with event was proposed. Based on the event model, the ontology of event is used to describe the connotation of function and to reflect the stability offunction. The variant of the event is used to represent the extension and to incarnate thevariety of function. The constaints of the ontology on the variant is used to reflect thedialectical relationship between the connotation and extension of function. Thus theevent description model of product function was established. Then the classification andorganization of the event knowledge were studied, and the method of raising inventiveproduct originality based on the event model was proposed. The event functionalrepresentation is conducive to expand the design space, is convenient for spreadingassociation, and is contribute to obtain more innovative solutions and improve theefficiency of design.4. On the basis of the event functional representation, the function modelingmethod based on the event model was given. Based on a study of the diversity and thebasic processes of product design with the event model, firstly, the abstraction methodof the total function with the help of the event knowledge hierarchy tree was given.Secondly, by determining the decomposition principles and decomposition basis of theevent function, the event functional decomposition tree was established to express thefunction structure of the product, and the graphical representation, mathematicaldescription and solution algorithm, etc. were studied. Thirdly, combining the eventknowledge hierarchy tree, the concept and the expansion method of the event functionaldecomposition expansion tree were built and the reuse of the event knowledge was alsostudied. Theses methods can reduce the complexity of the design problem, arebeneficial to improve the design efficiency, and are able to expand the design space.5. The above models and methods were applied to the design of spatial deployableantenna and an intelligent tutoring system, and have obtained the satisfactory results.Firstly, the event representation and abstract of expand function of spatial deployableantenna was given, two originality of deployable antenna were put forward. Secondly,the proposed models and methods were applied to the research and development processof a network intelligent tutoring system, which improved the system’s intelligence andthe efficiency of its research and development. These two applications verified thecorrectness and effectiveness of the proposed models and methods.