故障信号

This paper studies wavelet method which detects leak fault for"four kinds of pipe"(reheater, superheater, waterwall, economizer) of power plant boilers and also leak fault for liquid metal in model of fast breeder reactor.

8结合实例利用小波分析进行电站"四管爆破"故障信号提取的研究，同时也进行了利用小波分析提取核电站快堆钠回路泄漏故障信号的研究。

To solve some problems in analysing fault signals of compressor,extraction and recognition of fault signal with Morlet continuous wavelet was proposed.

针对目前压缩机故障信号分析中存在的问题，提出了用 Morlet 连续小波对故障信号进行提取和识别。

On the basis of dual feature identification method, combined with small wave analysis, it effectively extracts failure features, analyzes the stability power failure vibration signal feature on the general Fourier atlas, analyzes the shock power failure vibration signal feature on the resonance modulating Fourier atlas, using small wave to analyze the shock failure vibration signal feature.

是一种在"双特征判别法"的基础上，结合小波分析，有效提取故障特征，进行诊断的"三特征判别法"，所述的故障信号"三特征判别法"就是：在常规傅立叶谱图上分析平稳功率故障振动信号特征，在共振解调傅立叶谱图上分析冲击功率故障振动信号特征，利用小波分析冲击故障振动信号特征。

By re-constructing the system, the residual error dynamic characteristics of unknown input and fault signals including unknown disturbances and modelling error are obtained. The energy norm indexes of disturbance and fault signals of residual error are selected separately to reflect the restraint of disturbance and the sensitivity of faults, and the design of fault detection observer is described as an optimization problem.

通过对系统进行重构，获取了包括未知扰动、建模误差等未知输入信号和故障信号的残差动态特性，分别选取残差的扰动信号和故障信号的能量范数指标来体现其对扰动的抑制作用和对故障的灵敏性，并将故障检测观测器的设计描述为一个优化问题。

In chapter 4, the Newlands harmonic wavelet is improved and a new type of wavelet with better time-frequency characteristic is constructed. Frequency band of signal can be divided arbitrary with the improved harmonic wavelet so that the phenomena of aliasing are reduced. Several typical fault signals in Electromechanical System are analyzed with it. In addition to the improved harmonic wavelet in chapter 4, a new half-complex wavelet is presented to improve the complex wavelet, which is given by Chaari.O. A unilateral recursive algorithm is derived to improve the real-time characteristic. A parameter n is imported to make the time-frequency and filtering characteristics of it better and its ability of extracting fault feature is enhanced.

第四章通过对Newland谐波小波的改进构造频域紧支撑、时域性能良好的新型小波函数，可实现信号频带的任意划分，从而减少频带混叠现象，采用改进的谐波小波对多种典型的机电系统故障信号进行了分析；以Chaari.O复小波为基础构造了一个半复小波，从提高复小波算法的实时性出发，推导了半复小波单向递推算法，通过给原小波设置可调参数的方法，实现了一种能满足小波基本条件的复值小波，可以通过参数的调整调节小波滤波器在Hilbert空间的时频特性和相应的滤波性能，以加强半复小波对故障特征的提取能力。

A fault diagnosis based on wavelet and PNN was introduced, which firstly uses Mexican Hat wavelet to transform diagnosis signal and extract energy normalized vector, then uses PNN to output fault as a classifier.

针对煤矿主通风机故障与征兆对应关系复杂的特点，以及利用传统BP网络进行故障诊断存在训练速度慢、易陷入局部极小的缺点，提出基于小波和概率神经网络的故障诊断方法：先利用时频两域有紧支撑能力的MexicanHat小波变换故障信号并提取能量归一化故障特征向量；然后将概率神经网络作为诊断决策分类器，输出故障模式。

Acorrding to the character that wavelet transform technique can localize thetime-domain and frequency-domain, it can focalize any detail of signals and can recognize theabrupt signal and nostationary signal. The characteristics of typical fault for the centrifugalcompressor rotor are extracted by wavelet transform, and the characteristics vector is foundedby using energy as element.

通过小波变换技术对时域和频域同时具有良好的局部化性质，可以聚焦到信号的任意细节，对突变信号和非平稳信号具有很强的识别能力，利用小波包变换对离心压缩机转子典型故障的振动信号进行特征提取，并以&能量&为元素，构造离心压缩机故障信号的特征向量，以便神经网络识别。

Exogenous fault mechanics model characterizes wave making vibration propagation process caused by structural defects, defines transmission and reflection property of stress wave during the propagation, and provides theoretical basis for determining and seperating various kinds of polygenetic wave speed, which can be used in inversion and location of structural fault with satisfaction. By comprehensively using the two types of fault model that we presented, this paper has satisfactorily solved the classification and recognition of polygenetic faults of rotary support.

内源性故障力学模型较好地说明了回转支承内部的各种故障的形成和发展机理，描述了故障存在时回转支承的振动激励响应特性，为多源故障信号的分类识别提供了一种理论模型，外源性故障力学模型描述了由结构缺陷引起的波致振动传播过程，解释了传播过程中应力波的传递与反射特性，为各类故障波速的确定与分离提供了理论基础，能较好地用于结构故障的反演与定位。

The concept of entropy is applied to define an index on evaluating the abnormal condition. Prediagnosis of machine fault is made using the spectral structure distribution divergence as a criterion, in which the J divergence concept and multi-parameter evalution theory that describe the pseudo distances between the sampling signals and the corresponding standard faulty signals are used.

为此，基于信息熵提出了一个机组起停车过程转子运行状态的评估指标，并在此基础上，为实现机组运行故障早期预诊的目的，进而基于J散度及多参数评估理论，提出了信号频谱结构分布散度的概念，以描述实测信号与机组典型故障信号间的伪空间距离，从而实现了机组运行故障的初步预诊。

It carves out more research and application chances for malfunction diagnosis system, and it has wide application foreground.

而且本文的信号是轴承的故障信号，对基于DSP6000的诊断系统是故障诊断中的一次大胆尝试，为故障诊断系统的进一步研究和应用开拓了空间，具有广阔的应用前景。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。