An extended case-based reasoning method and corresponding product design process

During product design process, conventional case-based reasoning (CBR) has shown significant applications in coping with new problems by recalling and reusing solutions in old context. However, conventional CBR still lacks effective methods to assist designers in generating creative design solutions of identified problems during modification stage. To make up for this deficiency, an extended CBR (ECBR) method characterized by two retrieval stages is proposed in this paper. The former retrieval stage is aimed to retrieve the most similar source case for design reusing, and the latter one is designed to assist designers in searching for relevant function units to generate creative design ideas for final design solution. A five-tuple knowledge model of product case is presented. It includes both specific design information for design reusing and abstract function units for generating creative design ideas. To effectively organize these case information, a hierarchy knowledge model of case base is established. It consists of case type layer, product case layer, and function unit layer. A corresponding retrieval strategy is presented to deal with different retrieval goals. To improve the performance of ECBR method in modification stage, the substance-attribute-function-cause analysis model and TRIZ tools are integrated together to aid problem analysis and problem-solving of retrieved product case. Finally, a new product conceptual design process is proposed based on ECBR method and the conceptual design of a smokeless barbecue equipment is employed as an example to verify the feasibility and effectiveness of ECBR method.