Using Fuzzy Theory in %GR&R and NDC of Measurement System Analysis

ISO9001:2000 and TS 16949 have become the major quality system management models in present traditional and Hi-tech industries. The Measurement System Analysis (MSA) Reference Manual, on the other hand, is one of the core tools in ISO/TS 16949. MSA aims to evaluate Gauge Repeatability and Reproducibility (GR&R) where the control, monitoring, and maintenance of the measurement process are required in measurement systems so that the measurement capability could be ensured under statistical control. An ideal measurement system should present the statistical characteristic of zero error on any measured product. Nevertheless, such an ideal measurement system hardly exists. Managers therefore have to adopt such measurement systems with unsatisfactory statistical characteristics. Traditional MSA indexes are constructed with definite observed values. Nevertheless, measurements with observed values are not entirely error-free. For this reason, this study proposes to research three cases in a case company and apply the integration of Fuzzy Theory and GR&R to discuss the differences in the evaluation index GR&R and the Number of Distinct Categories (NDC). Substituting fuzzy numbers for definite numbers found that the data of %GR&R were increased and NDC was decreased after fuzzification. Such results verify that the fuzzified %GR&R and NDC become stricter in the determination criterion. The research outcomes could assist the case company in improving the reference data of measurement systems and promoting the measurement quality.

Resilience based importance measure analysis for SoS

In a system of systems(SoS),resilience is an important factor in maintaining the functionality,stability,and enhancing the operation effectiveness.From the perspective of resilience,this paper studies the importance of the SoS,and a resilience-based importance measure analysis is conducted to provide suggestions in the design and optimization of the structure of the SoS.In this paper,the components of the SoS are simplified as four kinds of network nodes:sensor,decision point,influencer,and target.In this networked SoS,the number of operation loops is used as the performance indicator,and an approximate algorithm,which is based on eigenvalue of the adjacency matrix,is proposed to calculate the number of operation loops.In order to understand the performance change of the SoS during the attack and defense process in the operations,an integral resilience model is proposed to depict the resilience of the SoS.From different perspectives of enhancing the resilience,different measures,parameters and the corresponding algorithms for the resilience importance of components are proposed.Finally,a case study on an SoS is conducted to verify the validity of the network modelling and the resiliencebased importance analysis method.

Vector-intensity measure based seismic vulnerability analysis of bridge structures

This paper presents a method for seismic vulnerability analysis of bridge structures based on vector-valued intensity measure （viM）, which predicts the limit-state capacities efficiently with multi-intensity measures of seismic event. Accounting for the uncertainties of the bridge model, ten single-bent overpass bridge structures are taken as samples statistically using Latin hypercube sampling approach. 200 earthquake records are chosen randomly for the uncertainties of ground motions according to the site condition of the bridges. The uncertainties of structural capacity and seismic demand are evaluated with the ratios of demand to capacity in different damage state. By comparing the relative importance of different intensity measures, Sa（T1） and Sa（T2） are chosen as viM. Then, the vector-valued fragility functions of different bridge components are developed. Finally, the system-level vulnerability of the bridge based on viM is studied with Duunett- Sobel class correlation matrix which can consider the correlation effects of different bridge components. The study indicates that an increment IMs from a scalar IM to viM results in a significant reduction in the dispersion of fragility functions and in the uncertainties in evaluating earthquake risk. The feasibility and validity of the proposed vulnerability analysis method is validated and the bridge is more vulnerable than any components.

Application of wavelet analysis to fault diagnosis of angular measuring system

For fault diagnosis, signal singularity and irregularity discontinuity fraction are very significant characteristics of signal. The discontinuity of output signal represents a system fault . In an angular measuring system, function transformer uses two D/A convertors, output circuit fault of a D/A convertor brings about discontinuity of one phase input voltage amplitude of inductosyn, results in a system error exceeding the allowable error and reduces the system accuracy. This is the reason why discontinuity is detected. Fourier transform has no resolution ability in angular domain, but wavelet can analyse signal in angular and frequency domains. So we decompose the error signal of angular measuring system by wavelet, detect the signal singularity at high frequency layer and find out the accurate position of it.

Fault Detection Based on Hierarchical Cluster Analysis in Wide Area Backup Protection System

In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated quickly and defined exactly. In our study, global information will be introduced into the backup protection system. By analyzing and computing real-time PMU measurements, basing on cluster analysis theory, we are using mainly hierarchical cluster analysis to search after the statistical laws of electrical quantities' marked changes. Then we carry out fast and exact detection of fault components and fault sections, and finally accomplish fault isolation. The facts show that the fault detection of fault component (fault section) can be performed successfully by hierarchical cluster analysis and calculation. The results of hierarchical cluster analysis are accurate and reliable, and the dendrograms of hierarchical cluster analysis are in intuition.

Set-Membership Filtering Subject to Impulsive Measurement Outliers:A Recursive Algorithm

This paper is concerned with the set-membership filtering problem for a class of linear time-varying systems with norm-bounded noises and impulsive measurement outliers.A new representation is proposed to model the measurement outlier by an impulsive signal whose minimum interval length(i.e.,the minimum duration between two adjacent impulsive signals)and minimum norm(i.e.,the minimum of the norms of all impulsive signals)are larger than certain thresholds that are adjustable according to engineering practice.In order to guarantee satisfactory filtering performance,a so-called parameter-dependent set-membership filter is put forward that is capable of generating a time-varying ellipsoidal region containing the true system state.First,a novel outlier detection strategy is developed,based on a dedicatedly constructed input-output model,to examine whether the received measurement is corrupted by an outlier.Then,through the outcome of the outlier detection,the gain matrix of the desired filter and the corresponding ellipsoidal region are calculated by solving two recursive difference equations.Furthermore,the ultimate boundedness issue on the time-varying ellipsoidal region is thoroughly investigated.Finally,a simulation example is provided to demonstrate the effectiveness of our proposed parameter-dependent set-membership filtering strategy.

测量系统分析(MSA)在航天产品检测过程中的应用

文章主要介绍了测量系统分析(MSA)方法,并运用该方法针对有一定批量的航天典型产品,开展了MSA分析应用研究,明确了操作流程和步骤,通过改进测量系统,提升了测量系统的一致性和准确性,同时,明确了测量系统分析在航天产品的应用场景,为首件鉴定、九新分析提供了新思路新方法。

基于MSA对某螺纹孔位置度检具测量系统的应用分析及改进研究

由于曲轴结构复杂,目前国内外广泛运用位置度检具或三坐标测量机(CMM)用于曲轴过程尺寸检测,曲轴测量中一般以位置度检具为主,三坐标测量为辅;某发动机工厂增压改造项目中,新增的位置度检具需要通过测量系统分析(MSA),以确保位置度检具的稳定性、准确性、重复性、再现性满足测量系统分析(MSA)要求。MSA是由克莱斯勒、福特和通用汽车三大公司共同起草编制,目前MSA已更新至第四版。通过对改造项目中增加的曲轴法兰螺纹孔位置度检具测量系统分析(MSA),找出该测量系统的问题并提出改进方案,为曲轴产品尺寸控制及下线合格率提供了有力的数据支撑。

新型旋转激光扫描系统轴系调整与误差标定

旋转激光扫描系统是一种基于精密转台结合多路激光的空间多目标并行角度传感系统。为改善系统光源性能,设计了一种采用光纤从外部导入光源的新型轴系结构。但是当激光以一定角度穿过中空的转轴进入镜组后,若倾斜入射柱镜,将导致出射的扫描光面型发生变化。针对此问题,研究了一种基于平行线的传递性的激光光轴姿态的调整方法,并借助激光跟踪仪测量平台,分别对光轴与转轴轴系进行拟合,建立了对光轴倾斜误差的标定方法。实验结果表明,调整后光轴与转轴轴线的空间夹角优于0.15°,完全满足扫描光截面中心直线度对激光入射柱镜的角度要求。该调整方案可用于系统的装配环节,使扫描光更加接近理想平面,有助于系统测量精度的提升。

电池热释放烟气分析系统的校准

提出电池热释放烟气分析系统的校准方法。采用氧气、二氧化碳、一氧化碳、氢气、甲烷标准物质进行试验,选取示值误差、重复性、响应时间、零点漂移和量程漂移作为校准项目,建议计量技术指标:每种气体在量程内,示值误差为±3.0%,重复性不大于1.5%,响应时间不大于30 s,零点漂移和量程漂移均为±2.0%。通过校准实例对校准方法进行验证,验证结果表明该校准方法切实可行,可为该类设备计量技术规范的制订提供参考。

高原滨湖城市社区低碳生态评价体系构建及应用

基于高原滨湖城市的低碳生态发展需求,梳理现有低碳生态社区相关理论,选取可量化指标,构建包括道路交通、自然生态、土地利用和基础设施4个准则项、16个指标项的高原滨湖城市社区低碳生态评价体系,并以大理市主城区22个城市社区单元为研究对象,综合评价其低碳生态情况,得出以下结果:22个社区整体呈现“核心-边缘”格局,9个低碳型或较低碳型社区均分布在核心街道(下关街道),外围社区得分沿苍山路和人民北路递减且多为高碳型或较高碳型社区,这些社区与城市空间形态相契合;22个社区各项指标存在显著差异,其中街道朝向符合气候及滨湖地形特征;下关街道公共服务设施集聚且设施能源使用效率高,在有限用地条件下呈现出“服务-就业”双中心的特点。针对评价结果,提出倡导绿色低碳出行模式、优化生态空间格局、复合提升土地利用效率和完善升级基础设施配置的策略,以期为高原滨湖城市社区的低碳生态发展提供参考。

曲轴综合测量机几何误差建模及敏感性分析

为提高曲轴综合测量机测量精度,针对其几何误差元素多,逐一进行补偿工作量大、过程繁琐等问题,基于多体系统理论和齐次坐标变换建立曲轴综合测量机的几何误差模型,采用Sobol敏感性分析方法进行分析,识别出对测量精度影响较大的关键几何误差项。通过对曲轴综合测量机随动测板不同位置处的误差元素敏感性系数进行分析计算,从21项几何误差中识别出10项对曲轴综合测量机测量精度影响较大的关键项,为合理经济地提高曲轴综合测量机测量精度提供依据。

测量系统分析(MSA)在卷烟工艺质量管理中的应用

为了解测量系统中的波动源及其对测量结果的影响程度,以期对测量系统进行明确判断,利用计量型和计数型测量系统分析方法,以卷烟综合测试台、烟丝填充仪和盒包透明纸缺陷标准为例,介绍了测量系统分析在卷烟工艺质量管理中的应用过程,并对Minitab生成的图形和会话窗口进行了分析和说明。测量系统分析应用数理统计方法科学地找出了引起波动的原因,为卷烟工艺质量的改进提供了帮助。

MSA在电能表误差检验中的应用研究

近年来电力市场不断发展和完善,电力体制改革不断深化,厂网分开、竞价上网等市场化运作方式对电能表的计量误差提出了新的要求,对电能表计量准确度的要求越来越高。本文对电能表误差检验的测量系统进行分析,将测试误差来源分解为四部分:电能表自身变差、电能表检验装置的再现性变差、误差测量的重复性变差以及电能表与校验台的交互作用变差。文章阐述了MSA在电能表误差检验中的应用并对其进行了研究。

基于航空发动机装配测量的MSA研究与分析

转子系统的装配是航空发动机大修的重要环节之一,良好的装配质量需要准确的零件测量数据作为支撑,因此需要对测量器具进行周期性的检定和校准。但测量过程是个复杂的系统问题,需要综合考虑操作人员、测量器具、测量方法以及测量环境等因素共同作用的影响,评估测量过程的误差来源。该文提出了运用测量系统分析(MSA)的工作方法,结合Minitab统计软件,对发动机高压转子的装配测量环节进行研究,从测量结果的偏倚、线性、重复性和再现性等角度进行探讨,判定了测量系统的工作状态,并验证了在现有条件下运用MSA方法实施持续质量改进的可行性。

EWMA控制图在MSA稳定性分析中的应用

针对传统的 Shewhart 控制图使用当前观测数据进行测量系统分析(MSA)的稳定性分析,不易检测出过程均值中存在的小偏移,而指数加权滑动平均(EWMA)和累计和(CUSUM)控制图考虑了历史数据,可以克服Shewhart 控制图在小波动情况下检测能力不足的缺陷:首先通过 Montle-Carlo 模拟计算控制图性能评价指标ARL(average run length),分析了 EWMA 和 CUSUM 控制图的优越性;然后给出了 EWMA 控制图在 MSA 稳定性分析中的实施步骤.示例分析表明 EWMA 在小波动时比 CUSUM 和 Shewhart 控制图更为有效.

测量系统分析(MSA)在化学分析管理中应用的探讨

探讨测量系统分析(MSA)在化学分析管理中应用(通常该方法在机械加工过程中使用)。本方法主要使用方差计算分析的方法对系统和个人的方差进行统计计算,并对铁精矿中TFe检验过程中系统的重复性、再现性、检验人员之间差异及系统测量能力作出分析,从而判定检验系统的状态、改进方向及系统可接受程度。该方法采用实际生产中的样品,排除以前使用标准样品带来的人为因素。通过对变差的方差分析和各变异分量情况、Xbar图、R控制图的分析系统的判定更客观。

基于主元分析的温室物联网空气温湿度传感器故障诊断

针对温室物联网测控系统中空气温湿度传感器受恶劣环境影响易发生故障的问题,研究温室物联网测控系统中空气温湿度传感器的故障诊断,保障温室物联网测控系统整体工作的稳定可靠性,提出一种基于主元分析的空气温湿度传感器故障诊断方法。首先对空气温湿度传感器数据进行主元分析,通过监控平方预测误差统计量的变化实现传感器的故障检测;再针对检测出的空气温湿度传感器故障数据,利用加权后的平方预测误差统计量来计算传感器的累积贡献率,并将其作为传感器故障识别的指标,识别出现故障的空气温湿度传感器。利用空气温湿度传感器数据在不同故障条件下进行传感器故障诊断方法验证,验证结果表明:所提方法可用于温室物联网测控系统中空气温湿度传感器偏差故障和漂移故障的检测,偏差故障的检测效果要好于漂移故障,偏差故障综合检测率为100%,漂移故障综合检测率为51.25%;同时所提方法能够正确识别出故障传感器,有效提高温室物联网测控系统中空气温湿度传感器故障诊断结果的准确性。

考虑不确定性情况下的故障树重要度分析方法及应用

为了度量底事件发生概率不确定性对顶事件的影响程度,在建立故障树概率组成函数的基础上,基于矩独立重要性测度提出了考虑底事件发生概率不确定性情况的故障树重要度分析方法。以某飞机结冰探测系统为例,利用所提出的重要度方法分析了底事件发生概率不确定性对该系统故障的影响程度,设计者可根据重要度结果更有针对性地开展分析与设计,同时也验证了所提方法的合理性。