提高全息谱分析精度方法的研究

全息谱是综合相位、幅值和频率信息的一种谱分析技术 ,是进行旋转机械状态监测与故障诊断强有力的工具之一。然而 ,精确地求解相位、幅值及频率是作全息谱的基础和前提 ,基于传统DFT方法是不能得到精确的值。作者研究了提高三者精度的方法 ,提出了整周期截断DFT方法的快速算法 ,通过软件的方式获取了精确的相位、幅值及频率 ,实现了全息谱。在工程上得到了运用 ,为旋转机械进行故障诊断提供了可靠的保证。     

二维全息谱在旋转机械故障诊断中的应用

通过对振动信号的处理、分析发现,旋转机械转子系统的振动信号经幅值谱、功率谱等传统的谱分析方法后,往往除了1倍频外还包括各次谐波及高倍频成份;引起转子系统振动信号中2倍频分量的因素很多,包括不对中、裂纹和电磁干扰等。直接从幅值谱等传统的谱分析方法很难判断2倍频振动分量的性质和原因。研究基于对中性良好的转子试验台,模拟了多种转子系统的故障,研究了二维全息谱以及轴心轨迹在旋转机械轴裂纹故障和碰磨故障诊断中的应用,结果证明所实现算法的有效性。     

阶比双谱及其在旋转机械故障诊断中的应用

双谱分析是处理非线性、非高斯信号的有力工具，然而，它是以分析恒频振动的稳态信号作为前提条件的，对分析旋转机械中广泛存在的变频振动信号（如旋转机械升降速信号）是无能为力的。而阶比双谱是一种分析变频振动信号的新方法，它将非稳态信号按等转角间隔进行采样，得到阶域中的稳定信号，再进行双谱分析；仿真显示该方法优于阶比谱和传统双谱。最后，将该方法成功地应用到旋转机械升降速过程的故障诊断中，实验结果表明该方法是有效的，阶比双谱可很好地分析机械振动的非线性非平稳信号。     

基于频谱细化和相位差校正的全息谱研究

针对全息谱在频谱密集情况下精度会降低的问题,提出了基于频谱细化和相位差校正的全息谱分析方法。该方法采用复解析带通滤波器选带细化方法对以阶次频率为中心的局部区间进行细化分析,通过提高频率分辨率来消除密集频谱对精确获取幅值、相位信息的影响,运用相位差法对细化区间内的最大谱峰进行频率、幅值、相位校正,准确地提取出各阶次的幅值、相位信息,最后合成全息谱图。仿真及对柔性转子试验台振动信号的分析结果表明,基于频谱细化和相位差校正的全息谱能有效提高其分析精度,更加精确有效地诊断旋转机械的故障。     

应用LabVIEW分析转子特征谱

介绍转子特征谱分析———全谱分析和全息谱分析的基本概念,它们是以不同方式对转子同一截面上互相垂直的两个位移传感器,所采集的信号进行融合分析的方法,和传统的谱分析相比能够识别更多的转子信息。阐述利用Lab-VIEW平台实现全谱分析和全息谱分析的方法。通过对汽轮机转子振动信号的故障诊断表明,全谱分析和全息谱分析是进行旋转机械故障监测与诊断的有力工具。     

大型机组诊断信息的深层次处理问题

指出了在大型旋转机械故障诊断中,付氏谱分析的局限性和缺陷,提出了用全息谱进行大型机组诊断信息的深层次处理,以获取故障信息。     

基于椭圆Fourier描述子的旋转机械振动信号分析

基于椭圆Fourier描述子,对转子同一截面上相互垂直的两个传感器测取的同源振动信号进行融合分析,从理论上推导出滤波轴心轨迹的表达式。研究对比全谱、全息谱和矢谱,建立三种谱分析方法的统一理论框架,给出三种谱分析方法的理论表达式,并设计利用一次快速Fourier变换实现三种谱图的数值方法。在融合全谱、全息谱和矢谱三种谱分析方法的基础上,提出基于椭圆Fourier描述子的矢椭谱分析方法,用于分析转子的同源振动信号。应用对比验证了矢椭谱的简洁可行性。     

基于Lab VIEW平台的转子特征谱分析

本文介绍转子特征谱分析即全谱分析和全息谱分析的概念。并阐述了利用LabVIEW实现特征谱分析的方法。它是进行旋转机械故障监测与诊断的有力工具。     

阶次包络谱在轴承故障诊断中的应用

旋转机械的升降速过程包含丰富的状态信息,因而旋转机械的升降速过程对于旋转机械的故障诊断具有独特的价值.将常规的阶次分析技术与包络谱相结合,提出基于阶次包络谱的齿轮箱故障诊断方法.首先对齿轮箱升降速瞬态信号进行时域采样,再对时域信号实行等角度重采样,转化为角域平稳信号,最后对角域重采样信号进行包络谱分析,就可提取轴承的故障特征.通过对轴承内圈、外圈故障实验信号的分析,表明该方法能有效诊断轴承的故障.     

全息谱十年：回顾与展望

首先简要介绍了全息谱的产生,发展和十年来在回转机械诊断领域所取得的成就,对全息谱技术在因转机械故障诊断,起停车分析以及非稳态信息处理中的应用进行了全面的问顾和总结,最后,根据回转机械诊断的现状,对全息谱的发展方向进行了展望。     

平面端铣切削振动试验

介绍了端铣振动试验方法。通过观察分析工件表面的微观不平度、切削表面的高频波纹和在机床切削点测得的振动信号,跟踪分析了铣削强迫振动和颤振现象。强迫振动随切削速度、进给量、切削深度增大而加剧,颤振随切削速度、进给量增大及切削深度减小不易发生,结论与理论分析、他人试验结果相符,为选择改变切削用量、减小铣削振动指出了方向     

基于能量法的机械系统受振动时的可靠性分析

研究非线性机械系统受振动时，特别是受随机振动时的失效分析计算问题。对于受冲击式振动的机械系统定义了系统缓冲系数，从能量平衡的角度计算确定非线性系统所需的缓冲长度；对于受随机振动的非线性机械系统，通过引进VanderPol变换，采用计算平均功率的方法，发现在一定条件下，系统新的变量将趋于一个联合马可夫过程，从而可建立起相应的FPK方程，求解该方程，采用穿越分析技术和Miner准则，可计算出系统因随机振动而导致的疲劳破坏概率或平均失效时间。     

Investigation on Mesh and Sideband Vibrations of Helical Planetary Ring Gear Using Structure,Excitation and Deformation Symmetries

Time?variant excitations in planetary gear trains can cause excessive noise and vibration and even damage the system on a permanent basis. This paper focuses on the elastic vibrations of a helical planetary ring gear subjected to mesh and planet?pass excitations. Motivated by the structure, excitation and deformation symmetries, this paper proposes dual?frequency superposition and modulation methods to capture the mesh and sideband vibrations. The transi?tion between ring gear tooth and planet is introduced to address the excitations and vibrations. The phasing e ect of ring gear tooth and planet on various deformations is formulated. The inherent connections between the two types of vibrations are identified. The vibrations share identical exciting rules and the wavenumber and modulating signal order both equal the linear combination of tooth and planet counts. The results cover in?plane bending and extensional, out?of?plane bending and torsional deformations. Main findings are verified by numerical calculation and comparisons with the open literature. The analytical expressions can be used to determine whether the sideband is caused by component fault or only by elastic vibration. The methods can be extended to other power?transmission systems because little restriction is imposed during the analysis.     

Comparison of vibration visualization methods for classification of chaos based on CNN

This study assessed methods for visualizing the vibrations for chaotic systems using a time series, fast Fourier transform (FFT), threshold recurrence plot, and unthresholded recurrence plot. The image classification was then performed using CNN, and the accuracy of each visualization method was compared and analyzed. The nonlinear behavior of chaotic systems was examined using the commonly known Van der pol, Rossler, and Duffing equations. The Lyapunov exponent was calculated for each model parameter change to determine the chaos. The classification accuracy was examined for the chaotic signal in each visualization method of the proposed architecture based on VGG 16 using the determined label and image. The classification accuracy for the chaos of each visualization method is the result of signals mixed randomly five times. FFT analysis showed the highest evaluation result.

     

散点图在工业企业生产管理中的应用

本文从实例出发，介绍了散点图和散点图在工业企业中的数据分析的方法，并建议对其在设备管理领域进行推广。     

HYDRAULIC ACTIVE GUIDE ROLLER SYSTEM FOR HIGH-SPEED ELEVATOR BASED ON FUZZY CONTROLLER

Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuzzy logic controller is developed. First the working principle of the hydraulic guide system is introduced, then the dynamic model of the horizontal vibrations for elevator cage with active guide roller system and the mathematical model of the hydraulic system are given. A fuzzy logic controller for the hydraulic system is designed to control the hydraulic actuator. To improve the control performance, preview compensation for the controller is provided. Finally, simulation and experiments are executed to verify the hydraulic active guide roller system and the control strategy. Both the simulation and experimental results indicate that the hydraulic active guide roller system can reduce the horizontal vibrations of the elevator effectively and has better effects than the passive one, and the fuzzy logic controller with preview compensation can give superior control performance.     

Fluid-induced instability elimination of rotor-bearing system with an electromagnetic exciter

This paper describes an experimental investigation of whirl elimination of a hydrodynamic bearing with an electromagnetic exciter (EE) and includes a stability analysis through a root locus plot. The test apparatus incorporates the EE, which provides additional stiffness through a PD algorithm in order to stiffen a rotating machine to resolve fluid-induced instability. The stiffness of the hydrodynamic bearing gives a significant contribution to the occurrence of unstable vibrations as the speed or the load of a rotating machine increases. With regard to the whirl-eliminated investigations, the EE used to raise the stiffness of the rotating machine can cause important changes in the stability of the rotating machine. The threshold of stability derived in this paper that affects stability conditions can be used to define the stability margin of the rotating machine. A simple control scheme is used to calculate the amount of the supplemental stiffness supplied by the EE, and is confirmed through experiments. To offer a faster, more stable and more effective strategy for whirl elimination, the dynamic behavior of a rotor system affected by fluid-induced whirl instability phenomena has been successfully studied.     

基于四端网络法的汽轮发电机扭振特性仿真

基于四端网络模型和机械阻抗方法,提出了一种分布参数的汽轮发电机轴系扭振模型,并研制了相应的仿真软件包,可分析汽轮发电机扭振的各阶固有频率,振型及应力分布等性能,一种精确的低阶模型,算法简便快捷,所编软件包实用性强,可用于实际汽轮发电机轴系扭振的仿真研究。     

Compound rub malfunctions feature extraction based on full-spectrum cascade analysis and SVM

The acceleration signals of operational rotor vibration provide a lot of information about its running behaviour. The acceleration signal features of identification and extraction in the process of speed change are important for the fault diagnosis of rotating machinery. The full-spectrum cascade analysis of rotating machinery vibrations is an efficient method that enables the symptoms of some special types of fault (especially for rub) to be clearly detected. Some typical compound rub malfunctions have been researched by experiments in this study. Acceleration signals have been received by the experimental apparatus and analysed by full spectrum. The abrupt changes in surging acceleration signals of rotor malfunctions can be detected and their fault feature spectra shown in full-spectrum cascade plots. The full-spectrum experimental data are applied to the support vector machine (SVM) training to be classified. The results indicate the potential and feasibility of this approach for the diagnosis of rotor malfunctions. The full-spectrum cascade plot can enhance the feature information for the knowledge base of the rotating machinery rub fault diagnosis system and is of great significance to diagnose compound rub faults in a rotor more accurately.