Study On Evaluation Method And Key Technology For Alternative In Concept Design Of DFQ

Design for quality(DFQ) is the quality-oriented design methodology. Evaluation is one of the important actions in DFQ, it can check on the quality of product. At the same time, work in early stage of product design can affect the quality of product profoundly. Base on a wide exploration of present achievements and the developing trend in the field of product evaluation, this dissertation makes a systematic and deep-doing study on concept evaluation of DFQ.In chapter 1, the statue of this study is introduced. Base on the exploration of present achievements in the field of product evaluation, the developing trends and hotspot are pointed. The main research contents-concept evaluation method of QFD and key technology is decided accordingly.In chapter 2, take into account the characteristic of uncertainty in the stage of concept design, considering the modern quality philosophy and process model of QFD, the demerit of existing methods are analyzed. Then the concept evaluation method of DFQ is put forward. According to model and key technology of the concept evaluation method, main research contents in this paper are proposed.In chapter 3, the customer's requirement analysis and relation of objects are analyzed. First, the methods of customer's requirement analysis are reviewed simply. Then, take into account the uncertainty, study the relations of quality attributes and design variables, constrain relations of design variables, weight relations of quality attributes and compensation relations of attribute preference. When analyze the relations of quality attributes and design variables, the method of relation analysis based on Rough set theory is put forward for the first time. Using the constrain transition method to analyze the constrain relations of design variables. Examples are given to illustrate how to use the^e methods.In chapter 4, space mapping are studied take into account the uncertainty. When mapping from design variable space to quality attribute space in the stage of concept evaluation of product design, the combing qualitative and quantitative method, Rough Set based mapping method and physical model experimentation based mapping method are studied. When making physical model experimentation, the transformation method of system condition is put forward for the first time. When mapping from quality attribute space to preference space, Rough Set based mapping method and subjective mapping method are studied. The universal mapping method of qualitativeattribute is studied. Examples are given to illustrate how to use these methods.In chapter 5, according to the characteristic in the stage of concept evaluation of product design, the quality attribute preference aggregate model which support multi-attribute and group decision is set forth. According to the model, preference aggregation method based on evidential reasoning and Rough Set theory and rational evaluation method of multi-attribute and multi-evaluator are put forward. Consider the wave of evaluator's preference caused by uncertainty, robust of quality attribute and concept in the stage of concept evaluation are put forward for the first time. And the multiform formulae of robust are given. Examples are given to illustrate how to use these methods.In chapter 6, In order to use the preference information adequately in concept evaluation, the quality level of concept is introduced. Consider the uncertainty in the stage of concept evaluate, the definition of concept risk is given in the view of satisfied requirement. And the multiform formulae of risk are analyzed. When the concept choice is made, using risk index and not using the index are discussed. At last, examples are given to illustrate how to use these methods.In chapter 7, based on the above research, an computer aided concept evaluate system(CACE) is developed. Example of hydraulic pressure motor is used to illustrate operation of the system.In chapter 8, the important results and conclusions of the dissertation are summarized and the prospect of the research...