Case-based Scenario Knowledge Model Construction And Application In Product Form Design

Product form design is a human-centered innovative activity involving product form, human machine interaction interface and relevant aesthetics, human emotion and experience etc. As a cross-discipline in engineering, psychology, art and ergonomics etc, combined with image thinking and logic thinking, product form design becomes the focus in design engineering because of its complexity and ambiguity. Supported by"the National High Technology Research and Development Program of China"and"China Key Technologies R & D Programmer", aiming at product form design, the paper proposes the concept of design scenario based on the theories of case-based reasoning and cognitive psychology, builds up a case-based scenario knowledge model in product form design, and puts the model into design practices.The concept of"scenario"has been proposed in cognitive psychology and applied in some relevant fields such as artificial intelligence, product design and engineering. Scenario is an instant mental representation in human memory including all information and factors about the current human activities in the situation. In knowledge engineering, scenario knowledge represents and organizes knowledge by using some scenarios.On the basis of theory studies, the paper aims at a typical industrial product– NC machine tools, conducts the investigation and experiment of problem-solving process in product form design, analyzes the information process of product form design, the status/ effects of scenario and case, and demonstrates scenario knowledge representation and organization, which can effectively aid the image thinking, especially in the field of product form design. Then, a scenario knowledge structure in product form design was put forward on the basis of a design case study. The structure includes three parts: case scenario, scenario organization and scenario transformation which correspond to knowledge representation, acquiring and application. The"case scenario"is the representation of the case and the experience of a past designing experience; the"scenario organization"is an organization of design cases by index to satisfy the current designing requirements and needs; the"scenario transformation", combined scenario and the process of design knowledge application, is a process of aiding designers in a right situation with appropriate means.The paper has established a scenario knowledge model of product form design by the methods of human-centered product design, the mapping mechanism of"Behavior– Function– Structure– Process"in axiomatic design theory and the performance studies in psychology and ergonomics. The whole construction process includes five stages: design knowledge acquiring, case scenario construction, design scenario organization, scenario transformation model construction and its application of the model, which form a complete requirements identification, requirements transformation, model construction and model evaluation. First, designers'activities, requirements and knowledge were acquired by using the methods of cognition experiment, investigation and action analysis. Then, design case scenario is built up by the mapping mechanism in axiomatic design theory and design knowledge representation. Besides, design scenario organization structure is constructed by the case index, the designers'information processes and requirements. Furthermore, scenario transformation model is proposed based on the product form design process and designers'mental working studies. In fact, the case-based scenario knowledge model of product is a model of design action representation, modeling and application from design function and process. Finally, a computer aided product form design system– CBID is constructed to evaluate the reasonableness of the model.Theory and application experience both prove that the case-based scenario knowledge model in product form design can aid designing activities effectively, solve relevant difficulties of product form design and make progress in design theory research and practices.