The Study On Fuzzy Quality Function Deployment Technology Of Product Design

Quality function deployment (QFD) is a systematic customer-oriented method of product design. Through matrices named 'House of Quality' (HOQ) translation, Customer requirements are broken down into each stage of designing and manufacturing requirements step by step, and then the concurrent engineering of product development is put into practice. To solve the intrinsic fuzziness problem that is brought about by indefinite input information and subjective evaluation in the early stage of product design, through fuzzing information in HOQ which is the main clue of this article, the analytic and decision-making technology of HOQ in fuzzy environment is studied deeply and systematically.Based on analyzing the deficiency that traditional QFD which adopted exact digital scale cannot tackle the fuzzy problem effectively, according to linguistic variable expression style of HOQ input information and subjective evaluation way of HOQ constructing process, the comprehensive theoretic framework of fuzzy HOQ is founded. Surrounding each part of data fuzzing in building and analyzing process of HOQ and decision-making research of HOQ in the fuzzy environment, resolution methods are studied.Drawing and analyzing the customer requirements is the critical step in QFD. Normalized process and constructed expression method are the effective way. Utilizing fuzzy analytic cluster method can realize customer requirement items levels management. Customer requirement weights are the basic input information of HOQ. In this article, one-sided character is analyzed in subjective determination or objective determination method separately, and a reversal process method of fuzzy evaluation integrating subjective and objective factors is presented. The objective information is used to found the fuzzy relation equation. The subjective information is applied to deduce evaluation result. According to the principle of closeness optimization, the approximate weights are determined. The method can effectively use the subjective and objective information what can be captured easily. The example result proved the feasibility.Ranking the technical characteristic weights is the important output information of HOQ. Aiming to the problem that adopted fuzzy order relationship method to compare couples conducting complexly, this article brings forward an improved method. By founding uniform benchmark to refer and defining utility function, computing burden decreases largely. The problem of deficiency on ranking multiple technical characteristic fuzzy weights is solved. The reliability is increased.The deployment of technical characteristic target value is a complicated process with multiple variables and multiple objectives. Existent fuzzy factors in technical characteristic deployment of HOQ are analyzed in this article. A possibility linear program model, which comprehensively considers fuzzy objectives, fuzzy restricts and fuzzy coefficients, is presented. Incompleteness of partial fuzzy optimization is conquered. The simulation result shows that the acquired technical characteristic optimum deployment result is a changed improved region that comes along with the credibility and possibility.Product design is a process of multi-scheme evaluation and optimization selection. In order to supply HOQ to schemes evaluation, the structure of HOQ is reformed through substituting the schemes ranking matrix for the technical competitive analysis matrix. The relationship matrix is used to connect customer requirements to technical characteristics of schemes, and then customer-oriented schemes evaluation is realized. For solving the problem of schemes evaluation in the condition of incomplete information, a fuzzy schemes selection model based on HOQ is given. For the first time, the fuzzy technical characteristic weights outputted from HOQ and the quantitative or qualitative technical values of design schemes are utilized directly to found a fuzzy decision-making matrix. Hamming distance is used as measure tool. Fuzzy compromise method is adopted to implement fuzzy multi-attribute decision-making. Then, the aim of prioritizing the schemes in the early design stage is realized. Simulation study proved the feasibility and usefulness.Multi-functional team working pattern of QFD embodies group decision-making characteristics. In this article, the author researches the principles and methods of knowledge collaboration, and determines the rule of integrating evaluation results in advance and united decision-making afterwards. Considering inherent fuzziness of QFD process and each individual member's different preferences sufficiently, a scheme evaluation model using HOQ based on fuzzy group decision-making is put forward. Through weighting the integrated group information and weighting technical values, knowledge collaboration is carried out. The ranking of the schemes is determined by computing each scheme's relative closeness degree to fuzzy ideal solution. Simulation research shows that the model gives the practical way to apply the HOQ to designing schemes selection.