Application Research On Axiomatic Design And Its Integration With Robust Design

Product design is an important stage to determine the product performance, and effective product design can improve quality, reduce cost, and reduce time to market, whereas the design theories and methods play a major role in product design. Up to now, many design theories and methods have been presented. Among which the Axiomatic Design (AD) is a representative design theory. Axiomatic design offers a scientific base for design and improves design activities by providing the designer with a theoretical foundation based on logical and rational thought processes and tools. It is helpful to provide a systematic way of designing products and large systems, reduce the random search process, minimize the iterative trial-and-error process, make designers more creative and develop better designs and select the best design among good alternatives.Any design theory and method has its own characteristics and emphases. Furthermore, modern products tend to be more complicate, whereas the time to market and life cycle of products are reduced. As a result, it is difficult for the sole design method to satisfy the design requirements. Therefore, it is necessary to integrate different design tools of design theory and methods, so that the mutually combination of them has complementary advantages. Whereas revealing the inherent connection among the different design theory and methods is the base of achieving complementary advantagesUsing the relevant theoretical research achievements for reference, the axiomatic design theory and robust design method are deeply researched in this dissertation, in which the methods of evaluation and optimization design are introduced. The relation between axiomatic design and robust design is discussed and application of axiomatic design in other design fields, and a new approach to the theoretical research on robust optimal design is presented.The process of decomposition of domain elements and zigzagging mapping between neighborhood domains in axiomatic design are analyzed in detail, and the designing process utilizing Independence Axiom is expounded. By introducing axiomatic design into optimization design, a multi-objective optimization method based on axiomatic design is proposed. The contribution of design variable to design objectives can be calculated using orthogonal experiment and Analysis of Variance (ANOVA), and design variables are classified into groups and the number of groups is the same as that of the design objectives in order to make the design similar to the uncoupled or decoupled optimization design, which avoid of trade-off between design objectives.Then a new way of computing the information content is presented, which transforms numerical value from the fuzzy information by combining the theory of fuzzy mathematic and information axiom for the design is evaluated in quantity. For decision-maker, there is no need to provide the detail weighting factors of evaluation index and only through specifying their design and system range, the optimal design scenario can be selected according to the information contents. This approach allows the decision-maker to express preference flexibly.There exist some common concepts between axiomatic design and robust design. The relation between two axioms and robust design has been discussed thoroughly, and the inherent connection is revealed which indicates that the design satisfying the above two axioms is more robust. Furthermore, for several typical statistical distribution forms of product's quality characteristic, the mathematical relationship between the information content and quality loss as well as the relationship between information content and signal-to-noise ratio has been established. Due to the unification of axiomatic design and robust design, the virtue of axiomatic design for improving product quality can be promoted and the general application of robust design can be extended.In addition, robust optimal design is also studied in this dissertation. To solve implicit and high non-linear design function in engineering design optimization, a general approach for robust optimal design was proposed, which was based on tolerance model and orthogonal experimental method. Then for multi-objective robust optimal design, the loss function of multi-objective optimization is defined. According to the accordant relation between Information Axiom and quality loss function in the robust design process of product quality, that the total loss function of each sub-objective function is considered as objective function, and the approach of multi-objective robust optimal design based on axiomatic design and comprise decision support problem is proposed.Using the above methods, the design of portal crane is successfully accomplished. The case study indicates that the proposed methods are feasible and effective.