Case-based Decision Theory And TRIZ:a Coupling For Product Conceptual Design

Speed to market and innovation are two of the most important attributes that enable a manufacturer to be competitive. These two attributes can be contradicting, forcing compromises. Despite this, there exists one common activity which can benefit both attributes-optimize the decision-making process, which can satisfy rapid design and innovative design simultaneously. Decision-making occur in many places within the design process which is made up of task clarification, specification definition, conceptual design, and embodiment design. Within this process, conceptual design is the phase where decision-making and creativity can play an important role. Product conceptual design is a system work flow where specification of the design is the input and the conceptual design scheme of product is the output. The essence of product conceptual design is to acquire innovative design scheme of new products, and it will effect the quality and the market competitiveness of the final product. The main purpose of the research of product conceptual design is to standardized, formalized, and systematized the procedures, thus supporting designers to develop an innovative product which has a high quality and meets customer needs at the lowest expense of the time and the cost. This paper will develop the customer-driven product conceptual design process model by regarding the conceptual design process as a series of decision-making process, and mainly comitted to optimize related decision (Technical decision) problem resolution during the product conceptual design, thus helping designers rapidly formulate innovative design scheme for the new product development.The paper proposed a product conceptual design process model-QCTIS. Quality Function Deployment (QFD), Case-based Decision Theory (CBDT), Theory of Inventive Problem Solving (TRIZ), Image-Scale, and Solidworks are integrated into the process model. Specifically, a questionnaire design mechanism by utilizing knowledge-evelutionary laws and lines,40innovative principles, which come from TRIZ, to excavate unperceivable customer needs was firstly proposed. The mechanism is influenced by TRIZ as well as the Kano model to evaluate customer needs. Then, a CBDT-based problem resolution model to support general decision-making during product conceptual design, accordingly some methods used in the model were discussed, especially attribute scope determination related to similarity evaluation and similarity functions of each single attribute. In addition, based on the process of CBDT-based problem resolution model and the contradiction matrix comes from TRIZ, a CBDT-TRIZ model for rapidly undertaking innovative solution generation are proposed. Finally, the proposed process model QCTIS also utilizes QFD to translate customer wants into relevant engineering design requirements and thus formulating the design specification, and Image Scale to offer an orthogonal coordinates system to aid evaluation.Through some actual product designs, some software were developed based on the proposed product conceptual design process model, such as the tool for questionnaire design based on evelutionary lines and40innovative principles, the tool for general decision problem resolution based on CBDT, and a tool for the application of the CBDT-TRIZ model. The feasibility and effectiveness of the research result can also be proved by these tools. In addition, a "cordless hand-tool design" case study was developed to validate the new process model.