Research On Scheme Generating And Optimization Of Conceptual Design For Mechanical Products Based On Function-means Tree

Conceptual design is the primary stage of product development, the most critical part of product innovation, the main means of improving product quality and competitiveness, and always affects the survive and development of enterprises. Therefore, the research of conceptual design of product is very neccesary. Conceptual design of mechanical product includes two parts:schemes generating and schemes optimization. Schemes generating is a vital part of design process. The description of schemes generating process is advantageous to understand the idea of designer, accumulate and transfer design knowledge, and better able to guide the whole of schemes generating process. Schemes optimization is a post-processing stage of conceptual design and the important procedure of conceptual design, and can make decision in many schemes, which can obtain many more satisfactory schemes and lay the foundations for the next step of product design.Although a lot of theories, methods and tools was applies to schemes generating and optimization, but conceptual design is facing the challenges:it is not more in-depth to describe schemes generating, and faces incomplete information and difficulties of acquiring knowledge when solving schemes combinatorial explosion optimization problems. Therefore, the method of tree topology mapping process based on the function means tree was presented and schemes generating and optimization is discussed systematically in the paper by combining with improved ant colony algorithm and analytic hierarchy process (AHP). Main research results include:(1) According to the "Z" type mapping in axiomatic design, the tree topology mapping process is presented in improved function means tree and guided by the "Z" type mapping.(2)This paper analyzes schemes generating process by using tree topology mapping process, and then summarizes three-stage characteristics of schemes generating, proposes schemes generating process model based on directed graph.(3)This paper presents the graphic topology hierarchy structure, the schemes generating process model is applied to the tree topology mapping process by this structure which clearly expresses the hierarchy of FRs, the hierarchy of DPs, and the mapping process from FRs to DPs, finally, the scheme alternative figure of conceptual design which is recorded in the graphic topology hierarchy structure can be obtained by solving each schemes generating process model layer by layer.(4)Using metamodeling technology, a prototype system of graphic topology hierarchy structure is realized in GME, this system provides a simple modeling environment for conceptual design process.(5)this paper presents a scheme optimization method by combining with improved ant colony algorithm and AHP. The advantages of this method:it can make scheme alternative figure of conceptual design as scheme search space, be applied to the situations of incomplete information, and solve schemes combinatorial explosion optimization problems.Finally, the theories and tools presented in this paper was applied to the conceptual design of auto lifting and drilling fixture of pump, which analyzes schemes generating and optimization process, and verifies the feasibility and effectiveness of the theories and tools in this paper.