基于小波去噪的机车牵引电机轴承故障诊断仿真研究

轴承是牵引电机重要的传动部件,其性能直接影响机车的运行状态,机车运用时间过长,运行环境恶劣往往导致轴承不同程度的磨损、烧结,为降低牵引电机轴承故障率和机车维护成本,方便获取牵引电机轴承运用信息,本文提出基于小波去噪提取轴承特征的分析方法,利用LabVIEW编译软件对采集到的仿真试验台轴承振动信号进行小波包去噪处理,结合Hilbert包络分析提取去噪后信号的故障特征频率进行故障识别,为机车牵引电机故障诊断提供理论依据。     

某型号国产牵引电机轴承寿命对比试验

介绍了某型号国产牵引电机轴承与国外进口牵引电机轴承寿命对比试验方案,包括试验主体结构、试验头组件及试验润滑原理及方法等,并通过对试验数据及试验结果的全面对比,分析两种轴承的性能差异。试验结果对比表明,国产与进口牵引电机轴承在各项性能指标上无明显差别。     

机车车辆牵引电机轴承台架试验标准研究与解读

回顾了TB/T 3017.2—2016“机车车辆轴承台架试验方法 第2部分：牵引电机滚动轴承”起草前国内外铁路机车车辆牵引电机轴承的台架试验方法及其在2010年以来的运用状态,总结了该标准起草的技术思路并对技术方案的要点进行了解析,对牵引电机轴承风险分析的需求、基本方法、类别、门槛、意义等进行了解读,以实现牵引电机轴承精准的差异化管理,最后给出了TB/T 3017.2—2016的优化方向。     

广州地铁二号线A5型车牵引电机轴承电腐蚀问题调查分析及解决措施

广州地铁二号线A5型车采用株洲时代电气股份有限公司的牵引系统,主要由高速断路器、高压箱、电抗器、逆变器以及牵引电机组成。其通过牵引逆变器将1 500 V的直流电逆变为三相交流电供牵引电机电能,然后通过牵引电机将电能转化为地铁的动能。随着牵引电机运营时间的增加,时代牵引系统的稳定性开始降低,牵引电机轴承问题尤为严重。通过试验调查发现A5型车牵引电机轴承存在严重的电腐蚀现象,为解决此问题,广州地铁联合株机公司对此展开详细的调查与试验。     

动车组牵引电机用轴承检修周期间隔延长的分析

介绍了CRH2与CRH380A型动车组牵引电机轴承现行检修规程,对轴承润滑油脂加注量和周期进行理论分析,并各抽选两列动车组进行长期跟踪验证试验,通过考察补充油脂方式对延长轴承运行的能力,对牵引电机轴承检修周期延长至120万km进行了可行性分析。     

轨道牵引电机轴承试验研究

轴承考核评价试验方法与试验台架的研究,将对国产化进程起到积极的推动作用。通过分析目前国内轨道牵引电机轴承主要的试验项目与试验原理,提出了摩擦力矩试验等项目的典型试验台架安装结构;对未来试验的发展方向进行了总结和展望。     

新型卡板式外径千分表的设计应用

针对机车牵引电机转轴磨削测量中,对转轴轴承位尺寸超差的原因进行分析,设计制作机车牵引电机转轴新型卡板式外径千分表(实用新型:ZL201420477030.7)。实际应用表明,新型卡板式外径千分表保证了牵引电机转轴轴承位的磨削尺寸,避免了转轴轴承位尺寸超差现象,解决了机车牵引电机转轴轴承位磨削测量的工艺、质量问题。     

变工况下基于信息融合的地铁牵引电机轴承故障智能诊断

针对传统滚动轴承故障诊断方法过于依赖先验知识和专家经验,以及单一信号对某些故障识别率偏低的问题,提出一种变工况下基于信息融合的地铁牵引电机轴承故障诊断方法.首先搭建滚动轴承试验与多信息采集系统;其次对地铁牵引电机轴承进行缺陷预制并采集轴承试验过程中的声发射和振动信号;然后用小波包分解对原始信号进行处理并提取特征,再用卷积神经网络对归一化后的特征信息进行融合;最后建立二维卷积神经网络模型,对不同工况下的地铁牵引电机轴承故障进行智能诊断.试验结果表明:变工况下基于信息融合的地铁牵引电机轴承故障智能诊断方法,可在载荷和转速变化的情况下准确识别轴承的故障类型,当神经网络训练集与测试集涵盖工况相同时,准确度可达100％.     

机车牵引电机轴承润滑方式的改进设计

上海地铁线路牵引电机轴承失效概率较高,大部分电机轴承失效是由于润滑不良或电机轴承失效严重造成的,这给列车安全运行带来了极大风险。目前机车电机轴承润滑多采取静态注油方式,选择牵引电机轴承动态注油方式应优先考虑加油方法,故着重介绍一种通过控制器PICO-tronic进行自动控制动态注油的技术,该技术可以提高牵引电机注油质量与效率,保障列车运行安全。     

和谐与先锋号动车组牵引电机润滑脂对轴承运行的影响分析

通过对采用不同润滑脂的和谐200 km/h和先锋号动车组牵引电机轴承进行温升和耐久性台架试验,考核轴承长时间持续运行的能力.结果表明,具有自修复功能和憎水型的润滑脂对轴承中出现的轻微擦伤可以自行修复,降低润滑层中水分在高速接触点的瞬间高温破坏作用,提高了运行安全性,对牵引电机轴承润滑脂的选取具有一定的参考价值.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.