FAULT-TOLERANT PERFORMANCE OF DATA TRANSMISSION MODELS BASED ON REDUNDANT RESIDUE NUMBER SYSTEM

Fault-tolerant data transmission models based on the redundant residue number system are proposed in this paper; they can transmit data correctly between two ends unless the residue errors exceed the error-correction capability. The expressions for the probability of error are presented when the channel noise is additive Gaussian noise and each branch is M-ary orthogonal signaling modulation. The expressions of the probabilities of undetected and uncorrected error are also obtained when the redundant residue number system are single error-checking and single error-correcting model, respectively.

基于改进动态因果图的湿法冶金浸出过程故障诊断方法研究

针对现有湿法冶金工艺机制复杂和浸出工艺故障诊断方法存在精度较差等问题,研究了用改进的动态因果图诊断湿法冶金浸出工艺故障,主要通过二元区间数对动态因果图进行优化改进,并对条件概率上下限进行加权,实现湿法冶金浸出工艺故障诊断。结果表明:该故障诊断方法相较于常规方法,故障诊断准确率更高,能对浸出工艺的故障进行较准确的诊断。

借助弱纹理匹配的TEDS车底故障区域定位算法

针对当前动车组运行故障动态图像检测系统(trouble of moving EMU detection system,TEDS)故障识别准确率低的问题,本文提出一种借助弱纹理匹配的动车底部潜在故障区域定位方法。首先,采用拓扑交叉数检测大量弱纹理区域特征点;然后,以特征点为中心的环形区域内各像素点的拓扑交叉数值筛选特征点,构建相应特征向量进行弱纹理特征匹配;最后,对配准后的图像进行比对定位潜在故障区域。实验结果表明,该算法保证了匹配精度,能检测出大部分潜在故障区域,弱纹理区域的特征匹配准确率超过80%且所有图像对均存在特征匹配对,为以后的精准故障分类提供了有利条件。

基于小波包的电缆混合线路接地故障诊断方法研究

发生接地故障时负载电压数值会出现明显增大的情况,根据负载电压数值变化行为,提出基于小波包的电缆混合线路接地故障诊断方法。根据小波包分解与重构原则,对故障数据实施预处理,通过求解功率预测指标的方式,完成对电缆混合线路的短期故障功率预测。在故障属性集合中,判定故障行为表现特征,联合三角模糊数的计算结果,完成基于小波包的电缆混合线路接地故障诊断。对比实验结果表明,在小波包理论作用下,发生接地故障时负载电压数值达到了485 V,与非故障电压之间的差值超过100 V,电缆主机可以根据负载电压变化行为实现对混合线路接地故障行为的准确诊断。

一种自适应选取参数的改进变分模态分解方法

针对传统的变分模态分解(VMD)方法中模态数和惩罚参数难以确定的问题,提出了一种自适应选取参数的改进变分模态分解方法。首先,综合考虑了故障的冲击性和周期性特点,以Gini指数和谱峰比指标为基础构建了加权谱峰比(WSPR)指标;然后,采用非洲秃鹫优化算法(AVOA)进行了寻优,得到了最佳的模态数和惩罚参数组合,克服了人为主观选择参数的弊端;最后,在VMD分解信号后,利用加权谱峰比最大原则自适应选取了敏感内涵模态分量,对最佳IMF进行了包络解调分析,提取了滚动轴承早期故障特征,利用仿真信号、单一故障滚动轴承试验信号及复合故障滚动轴承试验信号对所述方法进行了验证。实验结果表明:该方法可以准确地提取出仿真信号的故障频率(100 Hz)、单一故障信号的故障频率(236.4 Hz)和复合故障信号的故障频率(内圈故障频率149.14 Hz、外圈故障频率86.39 Hz),并且在与其他方法和指标的对比中,其最佳IMF的包络谱图中故障特征频率及其倍数频的谱峰更加明显,准确率更高且鲁棒性更强。研究结果表明:该方法能够有效提取轴承早期故障信号的微弱特征,实现故障类型准确识别的目的。

基于三支决策和联系数的SFEP传递概率计算方法研究

为研究系统故障演化过程(System Fault Evolution Process,SFEP)中原因事件导致结果事件的传递概率,提出了一种基于三支决策和联系数的传递概率计算方法。根据三支决策思想将原因事件和结果事件划分为发生、不确定和不发生3种状态,将措施方案的作用划分为发生、不确定和不发生3种倾向;以联系数同异反分项系数分别代表上述3种状态和倾向,最终定量计算了传递概率范围。研究认为传递概率取决于原因事件的3种状态比例和措施方案的3种倾向比例。利用联系数的同异反分项系数分别描述了状态和倾向比例。总结了原因事件到结果事件状态的演化关系,形成了演化关系表。得到了导致结果事件3种状态的传递概率。以事件发生为目标,传递概率的最小值为导致结果事件发生的概率,最大值为前者加上不确定的概率。方法克服了原有传递概率计算面临的问题,其结果与实际情况相符。

长螺旋钻机成桩混合料堵管的模糊故障树分析

在钻探工程施工过程中,不可避免地会出现机械故障。采用故障树分析其原因是常用的方法之一。但工程施工中,往往数据不足或不注意保存这些数据,实际应用时难以赋值,只能进行定性分析。针对工程施工机械出现故障的模糊性和不确定性,用模糊数描述底事件的发生概率,提出一种基于三角模糊数的工程施工机械故障树分析方法。该方法通过专家、现场技术人员及操作人员的经验构造三角模糊数描述各底事件发生的概率区间,通过计算三角模糊数的中位数重要度,按重要度大小对故障原因排序,作为制定预防措施的依据。最后将其应用于长螺旋钻机成桩混合料堵管的原因分析,按模糊重要度对故障有针对性地制定预防措施。结果表明:重要影响因素排序与现场技术人员及操作人员的定性分析与判断相符。

基于模糊故障树的电驱动桥可靠性分析

为解决故障树分析时无法获取足够基本事件故障率的问题,文章研究提出模糊故障树分析法。通过将专家判断转化为具体的模糊概率值,从而确定基本事件的发生概率,并完成对故障树顶事件发生概率和关键重要度计算。以某重型卡车的电驱动桥为例,通过建立电驱动桥不工作的故障树,对模糊故障树进行定量分析,确定了影响系统可靠性的关键故障因素,为相关工作者提供一定的参考借鉴价值。

一种基于经验模态分解和局部极大值点数的配电网高阻接地故障检测方法

配电网高阻接地故障(HIF)因故障特征微弱而难以被常规装置检测到,容易引发过电压、火灾和人身触电等安全问题。本文提出一种将时频分解和阈值判断结合的HIF识别方法。首先,利用经验模态分解(EMD)对零序电流进行处理;然后,选取第二个固有模态分量(IMF)作为特征分量并进行高斯滤波;最后,统计特征分量的局部极大值点的个数来判断是否发生HIF。利用PSCAD/EMTDC软件搭建10kV配电网模型进行算法验证。仿真结果表明,所提方法能够以较高的准确率将HIF和一些常见的干扰事件区分开,并且在发生噪声干扰、采样率变化、系统中性点接地方式改变及系统网络结构改变的情况下,均表现出较好的适应性。

基于模糊综合评价的水下采油树结构可靠性分析

针对水下采油树结构可靠性分析,提出一种基于模糊综合评价理论的水下采油树结构可靠性分析方法。首先,通过分析不同厂家水下采油树构型,确定水下采油树的典型结构构型及组成,分析水下采油树在运行过程中所受的外载荷;其次,采用专家打分以及模糊综合评价法求得故障树底事件失效率,通过定量分析求解顶事件失效率、可靠度及可靠寿命曲线等可靠性指标;最后,对故障树进行重要度分析及失效率变化对系统结构可靠性的影响,结果表明:“树本体内磨损”的关键重要度最高,对系统结构可靠性的影响最大,是结构中的薄弱环节,应予以关注。研究成果可为水下采油树结构的风险评估提供技术参考,对水下采油树的设计制造提供一定的指导意义。

系统故障演化过程中事件状态联系数构建研究

由于故障数据提取、表示、分析和处理过程存在不确定性,给系统故障演化过程研究带来困难,为此,提出一种基于集对分析联系数的系统故障演化过程事件状态联系数构建方法。基于联系数对多语义状态划分及同异反状态的表示分析能力,以系统安全为目标进行研究。分析已有精确系统故障演化过程分析方法的不足;将事件发生概率分布划分为安全、不确定、不安全三状态等效同异反状态,进而确定状态分项系数得到事件状态联系数;通过同异反真值表确定结果事件状态联系数。结果表明,得到的事件状态联系数符合联系数构造条件和逻辑真值关系,进而获得系统故障演化过程的事件演化表示方法,也可使用集对分析的已有方法进行相关研究。研究搭建集对分析理论与系统安全分析的桥梁,将蕴含不确定数据的定量分析发展为不确定性分析,化简分析过程并体现同异反特征。

Reliability Analysis of Hydraulic System of Anchor Drilling Rigs Based on Fuzzy Fault Tree

Considering that the fault phenomenon of the power head cannot feed under actual working conditions,fuzzy mathematics theory is introduced into fault tree analysis(FTA)according to the structural characteristics of hydraulic system of anchor drilling rigs in this paper.The triangle fuzzy number is used to describe the fault probability of the basic event,the fuzzy probability importance of the basic event is calculated,and the basic events are sorted by comparing the magnitude of the fuzzy probability importance.The results show that the gear wear of auxiliary oil pump,suction phenomena of gear pump,wear and leakage of No.1 and No.3 pumps are the key factors leading to power head failure.In order to improve the overall reliability of the hydraulic system,fault diagnosis and maintenance decisions provide a theoretical basis.

Assessment of gas and dust explosion in coal mines by means of fuzzy fault tree analysis

During the past decade, coal dust and gas explosions have been the most two serious types of disasters in China, threatening the lives of miners and causing significant losses in terms of national property. In this paper, an evaluation model of coal dust and gas explosions was constructed based on a fuzzy fault tree by taking the Xingli Coal Mine as a research site to identify the risk factors of coal dust and gas explosions.Furthermore, the hazards associated with such explosions were evaluated for this particular coal mine.After completing an on-site investigation, the fuzzy probabilities of basic events were obtained through expert scoring, and these expert opinions were then aggregated as trapezoidal fuzzy numbers to calculate the degrees of importance of all basic events. Finally, these degrees of importance were sorted. According to the resulting order, the basic events with higher probabilities were determined to identify key hazards in the daily safety management of this particular coal mine. Moreover, effective measures for preventing gas and coal dust explosions were derived. The fuzzy fault tree analysis method is of high significance in the analysis of accidental coal mine explosions and provides theoretical guidance for improving the efficiency of coal mine safety management in a scientific and feasible manner.

基于联合指标的滚动轴承振动信号重构及故障诊断

为了提高滚动轴承特征提取的有效性和故障识别的准确性,提出了一种基于联合指标的信号重构及基于CWT-2DCNN的故障诊断方法。首先,根据峭度和互相关系数构建出联合指标对通过集成经验模态分解(ensemble empirical mode decomposition,EEMD)得到的本征模态函数(intrinsic mode fuction,IMF)分量进行筛选与重构;其次,运用连续小波变换(continue wavelet transform,CWT)变换对重构信号进行时频域特征提取;最后,以时频特征图作为输入,构建基于卷积神经网络(convolutional neural network,CNN)的故障识别模型,从而实现滚动轴承故障的智能诊断。实验结果表明,提出的信号重构及故障诊断方法故障诊断正确率达到了99.48%,且在强噪声下仍具有较高的正确识别率,说明其具有较强的泛化能力。

Analysis of Syetem Reliability in Manufacturing Cell Based on Triangular Fuzzy Number

Due to lacking of test-data and field-data in reliability research during the design stage of manufacturing cell sys- tem.The degree of manufacturing cell system reliability research is increased.In order to deal with the deficient data and the un- certainty occurred from analysis and judgment,the paper discussed a method for studying reliability of manufacturing cell system through the analysis of fuzzy fault tree,which was based on triangular fuzzy number.At last,calculation case indicated that it would have great significance for ascertaining reliability index,maintenance and establishing keeping strategy towards manufac- turing cell system.

APPLICATION OF FUZZY SET THEORY IN FAULT TREE ANALYSIS

Based on the fuzzy set theory and the expand principle, using fuzzy number as the boundary condition of fault tree analysis, a new method of analyzing fuzzy fault probability of the top event is developed. Fuzzy importance analysis of the basic event is proposed as well. A practical example is given. This method is a new way to solve the obscure problems of fault tree analysis and has great value in engineering practice.

基于改进联合分布适应的轴承智能故障诊断方法

在轴承故障诊断过程中,存在缺乏足量故障样本、变工况下信号分布差异等问题。虽然基于机器学习和深度学习方法的智能故障诊断方法的运用取得了许多成果,但该方法在应用过程中仍面临一些挑战,阻碍了智能故障诊断方法在实际工业场景下的应用。为此,提出了一种基于改进联合分布适应的轴承智能故障诊断方法(BIFD-IJDA)。首先,利用小波包变换对振动信号进行了分解与重构,再计算了重构信号的统计参数,构成了原始特征集;然后,设计了基于特征重要度与KL散度的迁移特征选取方法,对各统计参数特征进行了量化评估;采用了改进联合分布适应方法,对源域和目标域特征集进行了分布适应处理,降低了域间分布差异;最后,利用源域特征样本训练的故障诊断模型预测了目标域样本故障类别,采用美国凯斯西储大学实验台和机械故障模拟(MFS)实验台的轴承故障数据,开展了不同工况下的故障诊断实验。实验结果表明:该故障诊断方法在2种轴承故障数据下取得的最大故障诊断准确率分别为100%和96.29%,明显优于其他对比模型。研究结果表明:该故障诊断方法具有应用于实际工业场景的潜力。

Fuzzy Risk Assessment Model of Power Transformer Based on Borda Number Theory

The power transformer is the key equipment of transforming voltage and exchanging power in the power system.It's safe and reliable operation directly influences the safe level of the power system.To study the risk assessment of power transformer which is very significant to improve the reliability of the power system,a fuzzy comprehensive risk assessment model of power transformer based on Borda number theory is proposed in this paper.At first,the fault types and risk factors of the power transformer are analyzed.Secondly,the basic framework of the fuzzy comprehensive evaluation is applied to quantify the risk factors.And then,Borda number theory is employed to analyze influence degree and occurrence probability of power transformer.At last,the various risk factors impact index and fuzzy comprehensive evaluation index of power transformer can be easily obtained.Applying this model,the relative importance degree of the risk factors can be horizontally compared according to the numerical index,the engineering staff can directly get the parameters of the transformer risk level and get a good description of the visual expression through using 5 score and similar visual language.

滚动轴承内圈局部故障渐变动力学建模与分析

当滚动轴承内圈出现局部故障时会产生复杂的振动响应,从滚动轴承内圈实际故障形貌的渐变性和非规则性的客观实际出发,引入位移激励函数定性分析滚动体通过故障区域时球心位置的渐变规律,采用随机数列表征故障底部形貌非规则性的特点,综合考虑轴承的径向载荷和滚动体通过故障区域时的打滑率等因素,建立了一种内圈局部故障渐变的轴承动力学模型。通过对比分析不同转频条件下实验和仿真数据的故障特征频率值,验证了局部故障渐变动力学模型的准确性。

基于T-S模糊故障树模型的场面监视雷达磁控管的故障推理研究

针对机场监视雷达磁控管运行时间短、实时运行数据难以大量获得的特点,为了实现雷达收发系统磁控管的快速故障推理分析,提出一种基于T-S模糊故障树模型的故障推理方法。利用该方法能够定性分析与定量计算的突出特点,采用新疆某机场场面监视雷达磁控管作为研究对象,对磁控管的故障事件及其可能造成故障的各个故障事件用相应的事件代码表示,并通过模糊数语言集描述这些事件,再根据事件关系所构建的T-S模糊故障树故障推理模型进行推理分析,最后通过实验结果验证该方法的可靠性和有效性。与传统的人工故障排查方法相比,其能够对磁控管故障事件进行更加全面且高效的推理分析。该方法为磁控管的故障推理分析在工程上的实践应用提供了新思路。