Robust Unknown Input Observer Design for Linear Uncertain Time Delay Systems with Application to Fault Detection

In this paper, a novel approach is proposed to design a robust fault detection observer for uncertain linear time delay systems. The system is composed of both norm‐bounded uncertainties and exogenous signals (noise, disturbance, and fault) which are considered to be unknown. The main contribution of this paper is to present unknown input observer (UIO)‐based fault detection system which shows the maximum sensitivity to fault signals and the minimum sensitivity to other signals. Since the system contains uncertainty terms, an H_∞ model‐matching approach is used in design procedure. The reference residual signal generator system is designed so that the fault signal has maximum sensitivity while the exogenous signals have minimum sensitivity on the residual signal. Then, the fault detection system is designed by minimizing the estimation error between the reference residual signal and the UIO residual signal in the sense of H_∞ norm. A sufficient condition for the existence of such a filter is exploited in terms of certain linear matrix inequalities (LMIs). Application of the proposed method in a numerical example and an engineering process are simulated to demonstrate the effectiveness of the proposed algorithm. Simulation results show the validity of the proposed approach to detect the occurrence of faults in the presence of modeling errors, disturbances, and noise.     

FAULT DIAGNOSIS OF HYDRAULIC SERVO SYSTEM USING THE UNSCENTED KALMAN FILTER

Fault occurrence can be embodied by the physical parameter variations of the hydraulic servo system. Faults can, therefore, be diagnosed according to the model coefficient variations of the hydraulic servo system. This paper proposes an approach for fault diagnosis based on the unscented Kalman filter (UKF) with a mathematical model of the hydraulic servo system. The mathematical model is established using the dynamic equations of the hydraulic servo system. Based on the fault mechanism analysis results, several important system model parameters that can separately represent different faults in different components of the hydraulic servo system are chosen. Discrete state space equations are derived from the dynamic equations. The UKF algorithm is used to estimate the important system model parameters of the hydraulic servo system by utilizing the discretized state space model. According to the variations of these model parameters, the fault modes and locations of the hydraulic servo system can be diagnosed and isolated. Two types of faults, namely, abrupt fault in servovalve gain and slow wear fault in hydraulic cylinder piston, which cannot be directly detected from the system output, are introduced individually to the hydraulic servo system in this work. By comparing with the extended Kalman Filter, three different experimental cases are used to validate the effectiveness of the UKF for hydraulic servo system fault diagnosis.     

火电厂发电机组常见的电气故障与维修研究

发动机组是火电厂各生产环节中重要的组成部分,其运行效率不但决定了生产效率,还关系着各类生产资源应用的有效性,对实现节能降耗具有重要意义,所以,必须加强对其运行稳定性的管理。分析了火电厂发动机组常见电气故障,并提出了相应的解决措施。     

浅析变电运行系统跳闸故障处理技术

变电运行与人们和社会生产的各个方面息息相关,而跳闸故障是变电运行中的主要故障。通过对变电运行系统中的跳闸故障进行分析,探讨了跳闸故障的处理技术,以供参考。     

电厂电气运行中常见故障分析及其应对措施探讨

为了保证电厂的生产效率,必须要分析电气的运行特征,确定电气故障发生的原因,综合考虑多方面因素,选择切实可行的措施解决问题。简要分析了电厂电气运行常见故障发生原因,并提出了相应的解决措施。     

粗集理论及其在旋转机械故障诊断中的应用 (二)旋转机械故障诊断知识库的形成

旋转机械故障诊断知识库形成的主要环节是信号的采集和信号的分析、整理 ;在所有的机械故障信号中 ,振动诊断技术是故障诊断的常用手段 ,对振动信号实现连续、在线诊断的最重要的数学工具是快速傅里叶变换(FFT)和小波理论。通过对实验的观察 ,建立转子故障特征向量和故障类型之间对应关系的数据库 ,为基于粗集理论故障诊断的决策表的形成提供了原始的知识库     

基于ITSS的故障智能诊断和处理系统的设计

如何以标准化的方式实施IT运维以提升运维服务的效率,对流程进行规范,是当前我国IT服务管理面临的迫切问题.文主要针对信息系统运维业务需求进行了分析,对支持ITSS的智能诊断和自动处理系统的开发和设计进行了详细阐述,以提高系统的运行稳定性.     

改进的局域均值分解在机械故障诊断中的应用

为了准确地提取出故障特征,把局域均值分解算法应用于机械故障振动信号的特征提取中.然而在对信号进行局域均值分解时,由于端点的趋势无法预知,在分解时会污染到整个信号序列,而且滑动平均造成了信号的过平滑处理,导致故障特征不能准确地提取.采用波形匹配解决端点处信号的走势,之后再利用线性插值求得信号的局域均值函数与包络函数,通过在Matlab环境下仿真调幅信号验证了该算法在端点处能很好的保持原有信号的特征;并采用实际的机械振动信号进行实验验证,引入端点效应评价指标,根据分解后的生产函数与原信号的相关系数验证了改进的局域均值分解更能准确地提取故障特征.     

随钻测量系统故障诊断装置

为了提高千米定向钻机随钻测量系统的稳定性,探讨了随钻测量系统的故障机理,并开发了一套基于嵌入式系统的故障诊断装置。该装置以单片机为控制核心,以UCOS-Ⅱ为软件构架,通过实时采集系统中关键参数来诊断故障所在。并通过图形和文本的方式显示在上位机上。结果表明该装置可以有效诊断系统故障所在。     

基于电力GIS的电网故障监控系统的研究与设计

电网故障监控系统利用故障采集器回传的电参数信息和地理标志信息,通过监控中心对这些信息读取处理后,导入GIS中,在显示器上通过GIS地图显示相关信息。从而帮助调度人员快速准确地发现和了解故障信息,及时制定抢修方案或启动抢修预案,并调度维修人员快速到达现场,可有效提高供电抢修效率,提升客户满意度,具有良好的应用价值。