基于物联网的机械故障检测仪设计

针对工业现场多机械设备同时运行,故障检测点多,空间分布范围广,数据传输实时性要求高等特点,设计了一种基于物联网的故障检测仪。检测仪使用M287作为控制核心,STM32F103作为振动信号采集系统,16位精度的ADS86841DBT对振动信号进行模数转换。其满足了振动信号采集高精度、高实时性的要求,支持温度、转速等多种信号的实时监测。故障检测仪以物联网为依托,实现了对多台机械设备分布式检测的功能。     

基于USB2.0的高速振动信号采集系统

文中设计了一种基于USB2.0的高速振动信号采集系统,对其中的USB2.0传输控制接口高速A／D转换和Lab-VIEW应用程序等进行了讨论,重点阐叙了USB控制接口的设计方法以及LabVIEW外部动态链接库DLL的编写和调用方法,并完成了基于CY7C68013芯片的采集分析系统。应用该系统与笔记本电脑相连即可进行振动信号的分析和处理,在机械故障诊断中具有较高的灵活性和实用性。     

基于LabVIEW与MATLAB的振动系统实验设计与开发

针对机械系统振动信号的采集分析问题,设计了机械振动软硬件实验采集分析系统。以滚筒洗衣机滚筒振动为例,采用传感器、电荷放大器和NI采集卡组成信号采集硬件系统,应用LabVIEW软件编写数据采集程序,对时域振动信号进行采集,应用MATLAB软件对采集到的信号进行频域的相关分析。     

超精密磨床系统振动监控及平衡技术研究

针对高精度磨削加工中磨床系统振动监控及主轴、砂轮平衡的需要,提出基于虚拟仪器设计的振动信号采集及分析系统。该系统由单片机的信号采集单元和上位计算机处理系统组成,具有加工状态实时监控、信号采集存储、信号分析处理、平衡计算、控制输出等功能。试验结果表明:系统的理论分析方法和功能满足设计要求。     

基于STM32F407的风机故障检测远程振动信号采集方法

针对工业上风机故障检测的远程振动信号采集需求,设计了一种基于相关算法的远程振动信号采集方法;STM32F407微控制器使用基频脉冲信号作为相位计算的基准,并使用64倍频脉冲信号作为模数转换的触发源,使振动频率无论如何变化采样频率都始终保持为振动频率的64倍;STM32F407微控制器完成采集后使用相关算法计算幅值和相角并通过SIM900A通信模块直接将结果和振动数据经由GPRS网络传输给上位机。实验表明,该方法可以实现振动信号的高精度远程采集。     

基于振动信号的变频涡旋压缩机故障诊断

设计开发了变频涡旋压缩机振动测试系统,该系统在LabVIEW软件平台上对变频涡旋压缩机振动信号进行采集和分析,可以实现涡旋压缩机变频控制、振动信号采集、数据读写和振动信号分析等功能。利用倒频谱法和互相关函数理论进行了振动信号实时分析和故障诊断,确定了振源,并提出相应减振措施,为涡旋流体机械的故障诊断及性能提高提供了方法和依据。     

基于C8051F350型单片机的振动信号采集系统

对一种在线监控振动信号采集装置进行了设计,建立了基于C8051F350型单片机的振动测量系统的结构,并对信号采集系统中CPU模块、采集模块、显示模块、通讯模块进行了分析.通过MATLAB对傅里叶变换(FFT)进行设计,对一些模拟信号进行了实测分析,实现了高精度模拟数据采集,可用于振动信号和各种电压信号的采集.该振动信号采集系统具有功能强大、成本低廉、高精度采集等优点.     

基于ARM架构的多通道振动信号采集与故障诊断系统设计

针对传统采集模块动态范围小、采样精度低、采样通道少等问题，设计了一套基于ARM架构的多通道振动信号采集与故障诊断系统。该系统硬件部分由STM32核心控制单元、压电式加速度传感器、信号调理模块和A/D转换模块组成，软件部分采用Visual Studio进行上位机设计。传感器采集振动信号数据，经A/D转换后传输至STM32微控制器，STM32通过网口模块将数据发送至PC。将振动信号通过传感器采集上来，对振动信号小波去噪然后进行时域和频域分析，分析获取传感器信号特征，根据振动信号振幅的有效值以及振动信号的频谱来实现故障诊断。并与普通得数据采集卡做了误差对比，实验结果表明：本文设计的系统可以达到97 dB的大动态范围信号采样，精度更好，有良好的实际应用价值。     

基于S3C2410X振动监测系统的设计

介绍了一种新型、实用、可靠的振动监测系统的硬件设计与软件设计。系统采用S3C2410X为控制核心，通过分析由LTC2414采集到的被测设备振动加速度信号监测设备工作状态。详细论述了系统振动信号的采集、处理电路的设计以及系统软件结构与功能，最后对系统的信号处理提出改进措施。系统已在实践中得到应用，达到了设计标准。     

磁流变阻尼器嵌入式传感器设计

分析了磁流变阻尼悬挂系统振动控制和故障诊断所需的状态监测参数,总结了磁流变阻尼器嵌入式传感器设计准则。在此基础上以某型履带车辆磁流变阻尼器研究对象,基于新型传感器技术对其进行了嵌入式传感器设计,优化了磁流变阻尼器控制决策和故障诊断过程中信号采集的方式,有利于提高信号采集的精度和可靠性。通过车辆悬挂装置单自由度振动试验,验证了嵌入式传感器设计方案的可行性,对于磁流变阻尼器在车辆悬挂系统的工程应用起到了重要的指导意义。     

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.