Fuzzy Design Method of Product Quality Robustness

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基于模糊K-均值算法的模糊分类器设计

基于模糊K-均值算法的模糊分类器,就是把目前比较常用的模糊K-均值算法的聚类方法,再一次与模糊分类规则提取相结合而得到的一种分类器。它是一种很有效的模糊分类器,训练样本能正确的分类。在这种方法中,首先用模糊K-均值算法按剖分和覆盖的原则把训练样本分成群,并且每一群的中心和半径都被计算出来。然后,设计一个用模糊规则来表示分类的模糊系统。这样就有效地构建了一个能对训练样本比较准确分类的模糊分类器。用这种方法设计的分类器不需要预定义参数、训练时间较短、方法简单     

基于鞍点逼近的机械结构可靠性稳健优化设计

将可靠性优化设计理论与可靠性灵敏度分析方法相结合,讨论了机械零部件稳健优化设计的问题.系统地推导了基于鞍点逼近的可靠性灵敏度公式,并把可靠性灵敏度计算结果融入可靠性稳健优化设计模型之中,将可靠性稳健优化设计归结为满足可靠性要求的多目标优化问题.在基本随机参数概率分布已知的前提下,应用鞍点逼近技术,得到极限状态函数的分布函数与概率密度函数,并且将此结果应用到机械零部件的可靠性灵敏度分析中,进而实现了机械零部件的可靠性稳健优化设计.通过与Monte-Carlo方法计算所得的结果相比可知,应用鞍点逼近技术可以迅速、准确地得到机械零部件可靠性稳健设计信息．     

A Robust Design Method in Product Quality Applications

1　IntroductionThe 1980bookletbyTaguchiwaswrittenatatimewhentheinitialsignal to noiseratioswerebeingdevel opedandhisthinkingwasbeingtranslatedfromJapaneseforthefirsttime.Histhinkingandourunder standingofhisthinkinghaveevolvedagreatdealduringtheensuing 2 1years.Taguchi′sapproachestooff linequalityimprovementhavegeneratedmuchinterestanddebateduringthelast2 1years.Foranaccountofthesetechniques ,seeTaguchiandWu( 1980 ) .Thishasinturnledresearcherstocloselyexaminehismeth odsandsuggestvariousimpr…     

Fuzzy logic-based FMEA robust design: a quantitative approach for robustness against groupthink in group/team decision-making

Group/team decision-making is an integral part of almost all failure mode and effects analysis (FMEA) projects. A dysfunctional aspect of this decision-making fashion in fuzzy FMEA is that group/team members’ designs for membership functions and IF-THEN rules may be overshadowed by a member’s design. This problem is caused by groupthink, a pitfall known by the Organisational Behaviour science. This study aims to develop a fuzzy FMEA approach which is robust to the problem. We applied the Taguchi’s robust parameter design and investigated the effects of various control parameters namely Defuzzification, Aggregation, And and Implication operators for the fuzzy inference system (FIS). Our experiments illustrate that the control parameters, in the above-mentioned order, have the most effect on the signal-to-noise ratio (SNR). These factors’ optimal setting consists of the Centroid, Sum, Minimum and Minimum levels, respectively.     

An enhanced fuzzy robust optimization model for regional solid waste management under uncertainty

In this study, an enhanced fuzzy robust optimization (EFRO) model is proposed for supporting regional solid waste management under uncertainty. This model is an extended version of robust optimization from a stochastic to a fuzzy environment, and novel in the following two aspects: (1) it uses multiple algorithms to tackle fuzzy constraints according to their characteristics; and (2) it incorporates fuzzy violation variables into the model, which could effectively reflect the trade-off between system economy and reliability. The regional waste management of the City of Dalian, China, was used as a case study for demonstration. A variety of solutions was obtained under various weight coefficients and confidence levels. From the case study, it was found that EFRO could help decision makers to design desired waste management alternatives under complex uncertainties. The successful application of EFRO in the studied real case is expected to be a good example for solid waste management in many other cities.     

多失效模式机械系统可靠性稳健设计方法研究

将机械系统可靠性设计理论和稳健设计方法相结合,讨论了多失效模式机械系统可靠性稳健设计问题,提出了多失效模式机械系统可靠性稳健设计的计算方法．把可靠性灵敏度融入可靠性优化设计模型之中,将机械系统可靠性稳健设计归结为满足可靠性要求的多目标优化问题．在基本随机参数的前二阶矩已知的情况下,可以迅速准确地得到机械系统可靠性稳健设计信息．     

A systematic approach to preliminary polymer process development: modeling and design

A general and complete methodology is presented to facilitate systematic modeling and design of polymer processes during the early development period. To capture and handle the subjective type of uncertainty, embedded in the preliminary process development, fuzzy theories are used as a basis to model and design the process in the presence of ambiguity and vagueness. Physical membership functions are developed for mapping the relation between process variables and the associated fuzzy uncertainties. Based on the qualitative results generated using our previously proposed “linguistic based preliminary design method,” the process modeling can be followed even in the absence of any process governing equations. The modeling is carried out by establishing an appropriate fuzzy reasoning system which provides a specific functional mapping that relates input process variables to one (or more than one) output performance parameter(s). A reduced yet feasible domain is generated by our qualitative design scheme to constrain the process variables. Now, any optimization routine can then be employed to search for a proper process design. We demonstrate the effectiveness of the proposed methodology by its application to a typical compression molding process.     

瓦楞纸板横切机速度控制系统设计

目的提高瓦楞纸板横切机速度跟踪精度,减小其剪切误差。方法基于模糊控制设计一个速度控制系统。介绍横切机的工作原理。针对其速度跟踪控制,阐述具体的控制算法。基于模糊控制设计一种速度跟踪控制器,以解决其非线性、数学模型不精确等问题,主要包括模糊化、隶属度函数、模糊规则等。以DSP为核心,搭建实验平台。同时详细阐述硬件电路结构,包括IPM模块、驱动隔离电路、速度和位置检测电路等。结果实验结果表明,即使存在干扰,控制系统仍可以在很短的时间内完成速度响应。同步区速度偏差较小、跟踪精度高。结论所述控制系统能够提高剪切效率、降低剪切误差,满足横切机的设计要求。     

基于模糊概率赋值的新型贝叶斯异常检测模型

提出了一种结合模糊决策与贝叶斯方法的异常检测模型，该模型将系统中与安全相关的事件进行分类，并以模糊隶属度函数的形式给出各类事件发生异常的实时置信度。异常检测系统综合某时刻所有实时概率取值，做出贝叶斯决策。同简单使用阈值方法的贝叶斯入侵检测模型相比，采用了模糊概率赋值的贝叶斯异常检测模型，在提高对问题描述的精确性同时，由于它对多种类型安全相关事件提供支持而具有更好的适应性，可以更全面地对更复杂的系统行为进行建模。     

自适应变论域模糊控制器在结构振动控制中的应用

大挠性航天结构具有复杂的动力学特性,建立其精确的数学模型是很困难的,模糊控制不需要精确的数学模型,但是模糊控制的主要缺陷是精度不太高,自适应能力有限,易产生振荡现象。变论域自适应模糊控制是改变模糊控制性能的主要方法之一,针对自适应变论域模糊控制器的稳定性设计这一难题,将输入和输出的隶属度函数分别用论域值表示成解析形式,引进李亚谱诺夫函数,设计了输入和输出的隶属度函数论域值的自适应律,针对大型航天桁架结构振动控制的仿真,结果表明设计的变论域模糊控制器是可行的。     

虚拟企业项目合作设计风险识别与评估方案

借助于价值链理论,进行了虚拟企业项目合作设计过程风险初步系统识别,并应用专家调查法和隶属度评价方法,识别出了项目合作设计过程关键风险因素;提出了基于四维特性的项目合作设计过程风险评估模型,并综合运用古林法和熵权系数法得出了四维特性的权重;在进行四维特性调查的基础上,采用模糊综合评价法进行了项目合作设计过程风险四维特性评估与风险度综合评估;探讨了基于投票理论的项目合作设计过程风险排序方案,并结合某开发类科研院所科技成果产业化项目合作设计实际进行了应用研究。     

An effective estimation of distribution algorithm for the flexible job-shop scheduling problem with fuzzy processing time

Considering the fuzzy nature of the data in real-world scheduling, an effective estimation of distribution algorithm (EDA) is proposed to solve the flexible job-shop scheduling problem with fuzzy processing time. A probability model is presented to describe the probability distribution of the solution space. A mechanism is provided to update the probability model with the elite individuals. By sampling the probability model, new individuals can be generated among the search region with promising solutions. Moreover, a left-shift scheme is employed for improving schedule solution when idle time exists on the machine. In addition, some fuzzy number operations are used to calculate scheduling objective value. The influence of parameter setting is investigated based on the Taguchi method of design of experiment, and a suitable parameter setting is suggested. Numerical testing results and comparisons with some existing algorithms are provided, which demonstrate the effectiveness of the proposed EDA.     

模糊可靠度隶属函数求解的迭代线抽样法

针对同时存在随机基本变量和模糊基本变量的结构,提出了一种模糊可靠度隶属函数求解的迭代线抽样方法.所提方法首先求得给定隶属度水平下模糊基本变量的取值域.然后通过优化建模和迭代策略,求得使功能函数取最值的模糊基本变量取值点,并求得对应的缩减后的随机变量空间内功能函数的设计点.最后基于功能函数最值对应的模糊基本变量取值点及其...     

Tough customers: good designs

Good design and successful innovation have been shown repeatedly to be intimately linked to early and close consultations between design and representative customers. What has not been highlighted, and should be, is that the tougher and more demanding the customers are in their equirements, the better and more robust the designs will be, along with their probability of reinnovation and propensity for successful longterm commercial exploitation. To demonstrate this point the history of a number of innovations based on good (commercially successful) designs is examined in two rather diffent industrial sectors — aerospace and agricultural machinery.     

Robust design with imprecise random variables and its application in hydrokinetic turbine optimization

In robust design, uncertainty is commonly modelled with precise probability distributions. In reality, the distribution types and distribution parameters may not always be available owing to limited data. This research develops a robust design methodology to accommodate the mixture of both precise and imprecise random variables. By incorporating the Taguchi quality loss function and the minimax regret criterion, the methodology mitigates the effects of not only uncertain parameters but also uncertainties in the models of the uncertain parameters. Hydrokinetic turbine systems are a relatively new alternative energy technology, and both precise and imprecise random variables exist in the design of such systems. The developed methodology is applied to the robust design optimization of a hydrokinetic turbine system. The results demonstrate the effectiveness of the proposed methodology.     

Principles of robust design methodology

The literature on robust design has focused chiefly on the development of methods for identifying robust design solutions. In this paper we present a literature review of conflicts and agreements on the principles of robust design. Through this review four central principles of robust design are identified: awareness of variation, insensitivity to noise factors, application of various methods, and application in all stages of a design process. These principles are comprised into the following definition of robust design methodology: Robust design methodology means systematic efforts to achieve insensitivity to noise factors. These efforts are founded on an awareness of variation and can be applied in all stages of product design. Copyright © 2007 John Wiley & Sons, Ltd.     

声呐目标跟踪关联中的模糊关联方法

声呐目标跟踪关联是为了获得精确的状态和属性估计、完全和实时的态势和威胁评估。在多台声呐系统联合探测中,根据相同目标、不同观测具有相似特征,提出了声呐目标模糊关联算法。模糊关联能够处理模糊性和不确定性信息,求解具有相似特征目标的关联值。通过将探测目标的方位数据模糊化,利用观测的模糊量和模糊隶属度函数进行数据关联,计算关联时长内两台声呐探测目标方位的关联值,仿真分析验证了上述算法的有效性并取得了较好的实验效果。     

Fuzzy Reliability Analysis of the Shaft of a Steam Turbine

Field surveying shows that the failure of the steam turbine‘s coupling is due to fatigue that is caused by compound stress. Fuzzy mathematics was applied to get the membership function of the fatigue strength rule. A formula of fuzzy reliability of the coupling was derived and a theory of coupling‘s fuzzy reliability is set up. The calculating method of the fuzzy reliability is explained by an illustrative example.     

稳健设计方法及其在包装印刷机械设计中的应用

简要介绍了稳健设计方法及其在机械、机构设计中的基本模型,以卷筒纸印刷机折页机构设计为例,对稳健设计方法在包装印刷机械行业的应用进行研究和探讨。