The Research On Evaluation And Decision Technology Of Product Conceptual Design Schemes And Its Application

With the globalization of economic development, the competition in domestic mechanical market is becoming increasingly severe. In order to keep company's advantage in the competition, we must enforce innovative capability, shorten design cycle and increase degree of customization. At the same time, we have to reduce cost, maintain quality of product and good after-service. Conceptual design of product is justly a very important process that can meet these demands, and is considered a very critical technology that can indicate human's intelligence and determine how the product is in the process of product design. Therefore, we must evaluate a number of conceptual design schemes that are generated in the conceptual design stage of product, elect the best of them, and proceed the subsequent design of product based on the elected best scheme. So the final product can fit the demand of cutthroat competition of market. On the basis of current evaluation and decision theory, a full evaluation and decision method is put forward in this thesis aiming at drawing the best scheme from a number of conceptual design schemes.It is the final intention of developing products to meet the requirements of customers. In this thesis, the theory and method of evaluation and decision of conceptual design schemes are studied in detail based on the degree of meeting the customer requirements. First of all, evaluation and decision theory system is introduced and studied in detail, and indicate the evaluation and decision model in detail. Then, the importance of customer requirements in the evaluation and decision process is pointed out, and the customer requirements for evaluation and decision are confirmed by research, prediction and analysis etc. Based on them, the importance of customer requirements are ranked by the method of AHP, and propose a method that can modify the judgement matrix. At the same time, the relations of customer requirements, evaluation metrics and design specifications based on customer requirements are studied, and an evaluation and decision model for conceptual design schemes based on satisfaction degree of customer requirements is proposed. At last, a full evaluation and decision method based on customer requirements is proposed. For customer requirements etc that are difficult to be measured in ration, this thesis uses the fuzzy sets to measure them, and BP neural network is utilized in the process of fuzzy reasoning to improve the calculating efficiency. The validity and usability of the evaluation and decision method presented in this thesis are verified by the example of the front suspension fork of mountain bike.This study supplements the evaluation and decision technology of conceptual design schemes. And the theory basis and detailed steps for evaluation and decision based on customer requirements are presented here, which are promotions to the technology and method of evaluation and decision used in product design.