Variable reconstruction and sensor fault identification using canonical variate analysis

The detection and identification of faults in dynamic continuous processes has received considerable recent attention from researchers in academia and industry. In this paper, a canonical variate analysis (CVA)-based sensor fault detection and identification method via variable reconstruction is described. Several previous studies have shown that CVA-based monitoring techniques can effectively detect faults in dynamic processes. Here we define two monitoring indices in the state and noise spaces for fault detection and, for sensor fault identification, we propose three variable reconstruction algorithms based on the proposed monitoring indices. The variable reconstruction algorithms are based on the concepts of conditional mean replacement and object function minimization. The proposed approach is applied to a simulated continuous stirred tank reactor and the results are compared to those obtained using the traditional dynamic monitoring technique, dynamic principal component analysis (PCA). The results indicate that the proposed methodology is quite effective for monitoring dynamic processes in terms of sensor fault detection and identification.     

基于BP神经网络的水下机器人推进器故障辨识算法

常规无人水下机器人推进器故障诊断中,均假设推进器处于几种固定故障模式,这与实际推进器故障情况有较大差别。该文将信息融合故障诊断技术引入推进器拥堵故障在线辨识之中,提出基于BP误差反传神经网络（Error Back Propagation Network）信息融合在线故障辨识模型,将水下机器人控制信号和故障情形下的方向偏转率作为BP神经网络融合模型输入,其输出即为反应推进器故障大小的拥堵系数,不仅提高了故障辨识精度,而且对连续不确定故障实现有效辨识。     

Application of extreme learning machine for series compensated transmission line protection

This paper proposes a new approach based on combined Wavelet Transform-Extreme Learning Machine (WT-ELM) technique for fault section identification (whether the fault is before or after the series capacitor as observed from the relay point), classification and location in a series compensated transmission line. This method uses the samples of fault currents for half cycle duration from the inception of fault. The features of fault currents are extracted by first level decomposition of the current samples using discrete wavelet transform (DWT) and the extracted features are applied as inputs to ELMs for fault section identification, classification and location. The feasibility of the proposed method has been tested on a 400 kV, 300 km series compensated transmission line for all the ten types of faults using MATLAB simulink. On testing 28,800 fault cases with varying fault resistance, fault inception angle, fault distance, load angle, percentage compensation level and source impedance, the performance of the proposed method has been found to be quite promising. The results also indicate that the proposed method is robust to wide variation in system and operating conditions.     

Online monitoring and fault identification of mean shifts in bivariate processes using decision tree learning techniques

With modern data collection system and computers used for on-line process monitoring and fault identification in manufacturing processes, it is common to monitor more than one correlated process variables simultaneously. The main problems in most multivariate control charts (e.g., T ² charts, MCUSUM charts, MEWMA charts) are that they cannot give direct information on which variable or subset of variables caused the out-of-control signals. A Decision Tree (DT) learning based model for bivariate process mean shift monitoring and fault identification is proposed in this paper under the assumption of constant variance-covariance matrix. Two DT classifiers based on the C5.0 algorithm are built, one for process monitoring and the other for fault identification. Simulation results show that the proposed model can not only detect the mean shifts but also give information on the variable or subset of variables that cause the out-of-control signals and its/their deviate directions. Finally a bivariate process example is presented and compared with the results of an existing model.     

Fault detection and identification—A filter investigation

This paper develops a new active fault‐tolerant control system based on the concept of analytical redundancy. The novel design presented here consists of an observation filter–based fault detection and identification system integrated with a nonlinear model predictive controller. A number of observation filters are designed, integrated with the nonlinear controller, and tested before reaching the final design, which comprises an unscented Kalman filter for fault detection and identification together with a nonlinear model predictive controller to form an active fault‐tolerant control system.     

多因素集对分析的系统故障模式识别方法

为研究多因素影响下系统故障模式识别,根据已有故障标准模式对故障样本模式进行分析,提出基于集对分析联系数和故障分布的系统故障模式识别新方法。根据故障背景建立故障模式识别系统,分析故障样本模式与故障标准模式,确定联系度各联系分量,计算联系度和识别度,最后通过确定故障样本模式与故障标准模式关系完成识别。对某电气系统实例分析给出了方法流程,获得了模式识别结果,从而为有针对性的采取预防和治理措施提供了决策支持。     

基于主元子空间故障重构技术的故障诊断研究

针对基于主元分析(PCA)的统计性能监控法,由于不用过程机理模型的信息,因此,对故障诊断问题有难以在理论上作系统分析的缺陷,于是提出了一种基于主元子空间故障重构技术的故障诊断方法。利用故障子空间的概念,在故障重构技术的基础上,研究基于T~2统计量的故障诊断问题,提出故障识别指标和诊断算法。通过对双效蒸发过程的仿真监测,验证该诊断方法的有效性。     

一种基于数据重构的KPCA故障识别方法

针对核主元分析(KPCA)方法只能实现故障检测,但无法实现故障变量识别的问题,提出一种基于数据重构的KPCA故障变量识别方法。采用改进的数据重构方法对各参数进行重构,然后利用故障识别指数对监控参数进行故障变量识别。通过对某型涡扇发动机进行实验的结果表明,该方法能够准确识别故障变量,从而有助于维护人员分析故障原因,初步确定可能的故障源,大大缩短故障定位及排故的时间,可预防重大事故的发生。     

A novel diagnostic and prognostic framework for incipient fault detection and remaining service life prediction with application to industrial rotating machines

Data-driven machine health monitoring systems (MHMS) have been widely investigated and applied in the field of machine diagnostics and prognostics with the aim of realizing predictive maintenance. It involves using data to identify early warnings that indicate potential system malfunctioning, predict when system failure might occur, and pre-emptively service equipment to avoid unscheduled downtime. One of the most critical aspects of data-driven MHMS is the provision of incipient fault diagnosis and prognosis regarding the system’s future working conditions. In this work, a novel diagnostic and prognostic framework is proposed to detect incipient faults and estimate remaining service life (RSL) of rotating machinery. In the proposed framework, a novel canonical variate analysis (CVA)-based monitoring index, which takes into account the distinctions between past and future canonical variables, is employed for carrying out incipient fault diagnosis. By incorporating the exponentially weighted moving average (EWMA) technique, a novel fault identification approach based on Pearson correlation analysis is presented and utilized to identify the influential variables that are most likely associated with the fault. Moreover, an enhanced metabolism grey forecasting model (MGFM) approach is developed for RSL prediction. Particle filter (PF) is employed to modify the traditional grey forecasting model for improving its prediction performance. The enhanced MGFM approach is designed to address two generic issues namely dealing with scarce data and quantifying the uncertainty of RSL in a probabilistic form, which are often encountered in the prognostics of safety-critical and complex assets. The proposed CVA-based index is validated on slowly evolving faults in a continuous stirred tank reactor (CSTR) system, and the effectiveness of the proposed integrated diagnostic and prognostic method for the monitoring of rotating machinery is demonstrated for slow involving faults in two case studies of an operational industrial centrifugal pump and one case study of an operational centrifugal compressor.     

Faulted gear identification of a rotating machinery based on wavelet transform and artificial neural network

In this paper, a condition monitoring and faults identification technique for rotating machineries using wavelet transform and artificial neural network is described. Most of the conventional techniques for condition monitoring and fault diagnosis in rotating machinery are based chiefly on analyzing the difference of vibration signal amplitude in the time domain or frequency spectrum. Unfortunately, in some applications, the vibration signal may not be available and the performance is limited. However, the sound emission signal serves as a promising alternative to the fault diagnosis system. In the present study, the sound emission of gear-set is used to evaluate the proposed fault diagnosis technique. In the experimental work, a continuous wavelet transform technique combined with a feature selection of energy spectrum is proposed for analyzing fault signals in a gear-set platform. The artificial neural network techniques both using probability neural network and conventional back-propagation network are compared in the system. The experimental results pointed out the sound emission can be used to monitor the condition of the gear-set platform and the proposed system achieved a fault recognition rate of 98% in the experimental gear-set platform.     

Fast fault diagnosis for industrial processes applied to the reliable operation of robotic systems

Fault detection, identification and monitoring play a primary role in systems engineering. This also holds for advanced processes, such as robotic systems, with highest demands on reliability and safety. A method is presented for fast fault detection and location, due to the data deweighting in the identification procedure of the monitored process parameters and the iterative on-line calculation of the statistics of the fault detection scheme. This method has many advantages for microcomputer applications and guarantees a very early process fault detection. Application of the method to the fast fault detection of the de motor actuators of a robotic system is described.     

基于TSEOPM的在轨航天器故障预报方法研究

针对在轨航天器非线性系统的故障预报,提出一种基于时间序列事件征兆模式挖掘的在轨航天器故障预报方法,该方法以在轨航天器遥测数据建立状态监测时间序列,根据事件特征函数利用层次聚类算法挖掘出故障事件征兆模式,然后利用故障事件征兆模式对航天器的状态监测时间序列数据进行分析,判断是否为故障征兆点,从而实现故障预报;实验结果表明,该方法能有效地预测在轨航天器状态监测时间序列数据中的故障事件。     

嵌入式系统在液压状态监测与智能故障诊断中的应用

针对国产地F元轨采矿设备液压系统故障率高,而其检测和故障诊断手段落后的背景,提出了一种基于嵌入式系统的液搓状态监测与智能故障诊断模型,陔故障诊断模型通过没置在液压系统中的多源异质传感器实时采集设备特征信息,并采用模糊神经网络来实现数据的融合处理,诊断结果通过界而友好的LCD显示,实现了故障状态的实时岭测和故障的智能诊断。通过该故障诊断模型,有效地解决了无轨采矿没备液搓系统故障率高而其检测和故障诊断手段落后的问题。提高了设备故障诊断的自动化和错能化．增强了设备的市场竞争力。     

基于LabVIEW的工作面输送设备远程监测与诊断系统设计

针对现有工作面输送设备监测与诊断系统只能在井下现场使用的问题,设计了一种基于LabVIEW的安装于地面调度中心的输送设备远程监测与诊断系统;给出了由该系统与井下基于PLC的输送设备监测与诊断系统相结合构成的全矿井无人工作面输送设备监测与诊断系统的整体结构,分析了该系统与井下系统间的数据交换实现,介绍了在LabVIEW中运行BP神经网络故障识别的方法及SQL Server数据管理系统的设计。实际应用表明,该系统运行稳定,实现了在地面调度中心实时监测和综合诊断工作面刮板输送机、转载机和破碎机的工况。     

基于Zernike矩和SVM的测试波形识别

在电子设备故障诊断中,波形识别是进行故障诊断的重要依据。根据电子设备实时检测与诊断系统的需要,提出了一种基于Zemike矩和支持向量机的测试波形识别方法。采用基于区域的Zernike矩描述子提取测试波形的特征,通过Relief算法选择特征,构造特征集,运用支持向量机完成测试波形的识别。实验结果表明,该方法能够实现时域波形的自动识别,具有较高的识别性能。     

Data-driven realizations of kernel and image representations and their application to fault detection and control system design

This paper deals with the data-driven design of observer-based fault detection and control systems. We first introduce the definitions of the data-driven forms of kernel and image representations. It is followed by the study of their identification. In the context of a fault-tolerant architecture, the design of observer-based fault detection, feed-forward and feedback control systems are addressed based on the data-driven realization of the kernel and image representations. Finally, the main results are demonstrated on the laboratory continuous stirred tank heater (CSTH) system.     

一种基于关联频繁模式的振动数据流挖掘框架

针对大型滚转机器轴承故障诊断应用场景中传统故障识别技术通常存在诊断识别精度低的问题,在频域分析基础上提出了一种新的数据挖掘框架——关联频繁模式集挖掘框架（Associated frequency patterns mining framework, AFPMF）,由数据预处理、关联频繁模式集挖掘和故障状态监测组成。首先,在数据预处理过程中,AFPMF在时域上使用时间窗分块划分机械振动数据流,再使用傅立叶变换对数据流进行时频变换实现故障频率特征提取。其次,使用基于滑动窗的关联频繁模式树构建压缩树,求解关联频繁模式集,实现数据挖掘过程。最后,根据数据挖掘结果中出现的振动频率判别潜在故障,从而实现监测故障状态。通过对比AFPMF和传统方法在轴承故障诊断应用场景的实验结果可知,相比传统方案,AFPMF具有更优的故障识别性能。     

Fault detection in multi-sensor networks based on multivariate time-series models and orthogonal transformations

We introduce the usage of multivariate orthogonal space transformations and vectorized time-series models in combination with data-driven system identification models to achieve an enhanced performance of residual-based fault detection in condition monitoring systems equipped with multi-sensor networks. Neither time-consuming annotated samples nor fault patterns/models need to be available, as our approach is solely based on on-line recorded data streams. The system identification step acts as a fusion operation by searching for relations and dependencies between sensor channels measuring the state of system variables. We therefore apply three different vectorized time-series variants: (i) non-linear finite impulse response models (NFIR) relying only on the lagged input variables, (ii) non-linear output error models (NOE), also including the lags of the own predictions and (iii) non-linear Box–Jenkins models (NBJ) which include the lags of the predictions errors as well. The use of multivariate orthogonal space transformations allows to produce more compact and accurate models due to an integrated dimensionality (noise) reduction step. Fault detection is conducted based on finding anomalies (untypical occurrences) in the temporal residual signal in incremental manner. Our experimental results achieved on four real-world condition monitoring scenarios employing multi-sensor network systems demonstrate that the Receiver Operating Characteristic (ROC) curves are improved over those ones achieved with native static models (w/o lags, w/o transformations) by about 20–30%.     

Unmanned Underwater Vehicles Fault Identification and Fault-Tolerant Control Method Based on FCA-CMAC Neural Networks,Applied on an Actuated Vehicle

A novel fault diagnosis and accommodation method for unmanned underwater vehicles thruster is presented in this paper. FCA-CMAC (Credit Assignment-based Fuzzy Cerebellar Model Articulation Controllers) neural network is used to realize the fault identification for thruster continuous and uncertain jammed fault situation. A reconstruction algorithm based on weighted pseudo-inverse is used to find the available solution of the control allocation problem. To illustrate effective of the proposed method, two simulation examples of multi-uncertain abrupt faults are given in the paper.     

基于RFID电梯远程监测系统的设计与实现

介绍了一种基于RFID射频识别的电梯远程监测系统,重点介绍了点对点射频收发数据的过程。对该远程系统的总体构架进行了设计,并利用Visua1C++6.0完成了报警界面及电梯运行状况的显示,实现了对电梯的无线远程监测和故障码的收发。