异步电机运行状态监测实验系统设计

为了实时准确地对异步电机的运行状态进行监控,设计了基于传感器、PCI数据采集卡、Windows操作系统的实验系统.通过传感器检测电机运行状态参数数据如电流、温度、转速等,经过调理电路后的数据通过数据采集卡传输到上位机,上位机软件系统以VC++为开发工具,基于Windows操作系统,实现对检测数据的分析和处理.实验证明:该系统能够实现对电机参数的自动在线监测、记录、特征提取和实时显示等功能,在精度和实时性方面满足要求,能够模拟实现列车牵引设备实时安全状态监测的基本功能,达到了设计的目的和要求.     

列车安全运行监测装置结构设计

随着新一代LKJ系统的应用推广,列车安全运行监测装置也需进行优化升级与之兼容。因此有必要从系统层面开展列车安全运行监测装置优化技术研究,构建新型列车安全信息平台,兼容既有LKJ和新一代LKJ的应用,在上一代列车安全运行监测的基础上,优化系统架构,全面提升产品性能,提高列车安全运行监测装置通信的安全性和可靠性,实现监测装置与第三方设备的安全交互。通过制定统一的行业技术标准规范,明确规定列车安全运行监测装置与功能扩展插件(包括外围设备)的功能、性能、接口等技术要求和检验要求。     

货物列车制动监测数据收集与应用

货物列车车辆制动系统性能状态基本靠列检人员通过列车试验的方法来检查。因车载供电困难,完美的车载智能监测方案很难在货物列车上实现。最近,基于RFID低功耗技术,研制了一种货物列车空气制动系统车载监测装置,通过压力感测器采集列车管、副风缸、制动缸上游、制动缸下游四点的压力变化,将空气制动系统性能的特征数据经RFID传输到服务器。探讨应用监测数据智能识别制动系统的性能状态,实现货物列车制动系统健康状态管理,提高货物列车运行安全性和运营效率。     

煤机设备无线自供电状态监测系统

针对当下煤机设备状态监测系统时效性差、通信电缆铺设困难、需要定期更换电池等问题,提出了一种基于无线传感器网络与自供电技术的监测系统设计方法。系统由能量采集模块、无线传感器网络及监测上位机组成,通过能量采集模块收集煤机设备振动能量为节点电路供电,采用无线传感器网络与上位机实现设备关键状态信息的采集、传输与处理。测试结果表明,系统可在30 m有效范围内实现对煤机设备运行状态的实时监测,能量采集模块最大输出功率可达378 mW,能够有效收集设备振动能量实现系统能源自供给。     

基于电涡流传感器的钢轨形变实时监测系统设计北大核心CSCD

针对传统的接触式钢轨受力状态监测成本高、实时性差、影响列车行驶等问题,设计了一种非接触式钢轨状态实时监测系统。系统具有云端实时监测列车行驶过程中钢轨竖直方向和水平方向形变量和受力状态的功能。该系统由电涡流传感器采集列车经过时钢轨竖直方向和水平方向形变量,通过STM32系列主控芯片对数据进行处理,结合NB-IoT网络信号覆盖极广、可穿透地下等优点,采用MQTT轻量级物联网传输协议,构建了云端数据可视化界面,实现对列车运行时钢轨状态的实时监测,实验结果表明,该系统具有实时在线监测、低功耗、非接触、运行稳定等特点,满足设计的实际需求。     

牵引与桥梁上拱激励下城轨列车动力学性能研究

城轨列车的实时变速工况是极为普遍的运行状态,若仅以匀速工况替代,无法得到贴近实际的研究结论。为此,提出一种新的考虑内外耦合激励的动力学模型。建立单节车体模型及编组城轨列车模型,综合考虑牵引工况以及城轨列车通过高架线路时的桥梁徐变上拱长波不平顺,研究在该内外耦合激励下的车辆动力学性能。基于微元法思想,计算得到城轨列车牵引工况下的电机转矩及基本阻力转矩与运行时间的关系,得到合理的综合工况下的运行状态。研究结果表明,在变速工况下车辆的轮对磨耗数、垂向平稳性指标及轮重减载率均有所上升;在桥梁长波不平顺激励下,车辆垂向平稳性指标有所下降、轮重减载率升高,而对车辆横向平稳性指标影响较小。     

基于FPGA的数据采集系统

该文以SJ-90B水电机组状态监测装置为背景,设计了以FPGA为核心的数据采集系统,介绍了系统构成和各个部分的原理及实现方式。现场应用表明,该系统性能可靠,可以有效地采集和处理水电机组各种运行状态信息,为机组状态监测的实现打下了坚实的基础。     

基于DDE协议的列车牵引传动系统实时监测软件的研究

牵引传动系统是列车的核心部分,对其关键参数的实时监测对列车的安全、可靠运行起关键作用。根据牵引传动系统关键参数的测试要求,设计并完成了基于VC＋＋和InTouch混合编程的牵引传动系统关键参数的实时监测软件。分析了实时监测系统的硬件设计结构,提出了监测软件的设计方法,在VC＋＋和InTouch开发平台上分别实现了后端数据采集和前端数据显示功能,并通过DDE协议实现了两者之间的数据交换和协调功能。     

基于存储测试的弹丸运行状态参数测试

针对弹药自动装填系统运行状态监测的需求,研究了弹药自动装填系统运行时会影响到的弹丸各状态参数,根据测试原理与测试指标要求,设计了弹丸振动加速度和角速度存储测试装置。选择了合适的传感器与主控芯片,设计了相应的信号调理与A/D转换、存储和通信模块;设计了下位机采集、存储和通信模块;根据数据处理的需求,利用Lab VIEW设计了人机交互与数据处理、分析软件。最后,通过弹药自动装填系统实车测试实验,对设计的存储测试装置进行了性能验证。结果表明,设计的存储测试装置能够测量出弹药自动装填系统运行过程中的状态参数变化,可以作为弹药自动装填系统特性研究的测量工具。     

基于小波BP神经网络的城轨列车辅助逆变系统故障诊断

在研究城轨列车辅助逆变系统故障诊断模型的基础上,提出一种基于小波包和神经网络相结合的故障诊断方法.该方法首先对采集到的电压信号进行小波降噪,再经过小波包分解和重构,构造特征向量,以此为故障样本对BP（Back propagation）神经网络进行训练,实现智能化故障诊断.实验结果表明：该方法能够很好地诊断出城轨列车辅助逆变系统的故障类型,这为辅助逆变系统的故障诊断和故障动态监测提供了新的参考,具有一定的工程应用价值.     

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。     

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....     

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.     

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.