用于DCS远距离通信的RS485转光纤模块设计

针对在DCS系统中DPU与I/O卡件进行RS485通信会产生电信号的衰减、易受到电磁干扰,数据需要远距离传输的要求,设计了一种用于DCS远距离通信的RS485转光纤模块。该模块主要包含光模块、RS485通讯芯片和保护电路,通过光模块可以将RS485通讯芯片发送的电信号转化为光信号,实现DPU与较远距离的I/O卡件进行数据交互。实验结果表明：该模块可以实现数据的可靠传输,有效地解决了在远距离情况下集散控制系统主控与卡件稳定通信问题,具有较好的实用性。     

基于ARM的雷电三维电场数据采集系统的设计

对雷电三维电场进行同步数据采集与分析,可以为研究不同方向的雷电电场对电气设备的影响以及研究不同地形对雷电结构的影响提供重要参考。设计了一种能够对雷电三维电场进行同步数据采集的系统,该系统主要包括传感器模块、信号采集模块、数据传输与存储模块、上位机软件设计等。利用3个通道A/D实现了对3路电场信号的采样,通过ARM11控制高速A/D转换和FIFO的读写,并且利用QT和SQLite数据库设计了上位机软件,完成了对采集数据的管理。     

电磁探伤系统中FPGA同步采样系统设计

在线钢轨探伤中,需要在高速情况下同步实现电磁投影激励和弱磁信号检测.针对目前多路数据同步采集系统的局限,以Virtex-5系列的FPGA为核心控制模块,应用AD7760∑-△型模数转换芯片实现了精度为24位、最大采样速率高达20M的高速同步采集系统.给出了多路同步采集系统的实现框架及原理,针对目前高速数据采集系统存在的采集和速度、资源利用不合理以及硬件成本较高等问题,给出了一种同步采集的方法.实验表明,该方法实现了多通道,高分辨率并行高速A/D同步采集的有效控制,满足了在线钢轨探伤系统对高速情况下,实现同步电磁投影激励和弱磁信号检测的要求.     

风挡加温控制器模拟及测试系统设计

设计了一套民用飞机风挡加温控制器地面功能模拟与测试系统。以PXI总线控制器为主控计算机,利用数据采集卡采集/模拟需要的信号,通过继电器进行开关量信号以及故障信号的模拟,利用移动客户端远程控制模拟器的运行。介绍了风挡加温控制器的模拟器硬件设计,包括电源模块的电路设计、I/O模块的电路设计。     

基于STM32和LabVIEW的多通道数据采集系统设计

为了满足生物行为研究和仿生行为研究中海量数据的实时采集与传输需求,搭建了基于STM32和LabVIEW的多通道数据采集系统。系统选用4块ADS8528模数转换芯片扩展STM32采集通道的数量从而实现多路信号的同步采集,通过无线传输模块将采集的数据上传至上位机。上位机选用LabVIEW图形化编程语言进行设计,通过UDP通讯协议接收下位机采集的数据并对数据进行分析和处理。通过实验验证：该数据采集系统能够实现单路630 kSPS,32路106 kSPS转换速率,模数转换误差在0.3%以内,无线网络传输功能正常,能够满足使用需求。     

基于CPLD的自定义PLC模拟I/O模块的研究

讨论了一种基于CPLD的自定义PLC模拟I/O模块设计。给出了系统的整体解决方案,设计了数据采集模块的软、硬件,实现的数据采集模块和PLC的双向数据交互,突出了采用CPLD实现用户自定义模拟I/O端口的功能。实验证明:基于CPLD的自定义PLC模拟I/O模块设计柔性好,性价比高,具有良好的实用价值。     

视频与多种物理信号的采集及后期耦合方法

为便于对某种非均质复合棒形组件的剪切过程进行实时监测与后期分析,提出了一种基于LabVIEW的视频与多种物理信号的采集及后期耦合分析方法。信号采集模块以主/从设计模式和同步触发模式为主体结构,实时同步采集、处理、显示并存储视频和多种物理信号;数据耦合模块通过图像处理工具与图像属性节点相结合的方式自动读取视频文件、提取视频成分,并将视频与其他物理信号进行时域耦合分析。经试验验证,此方法实现了视频与多个物理信号的高精度实时同步采集及回放;并结合实时视频,快速准确地分析了各物理量的动态变化规律。     

多通道环境下油样检测光谱分析系统的方案研究

对于光谱仪的信号采集系统的两个关键技术指标是微弱光电信号的处理和多通道数据的同步采集和传输。在分析信号采集的工作原理基础上，结合工程应用，研究了用于直读光谱仪的多通道数据采集与处理系统。基于微弱光电信号的特性和系统性能指标的需求，设计了以FPGA为控制核心、信号调理模块增益可控、多通道数据并行采集、实现数据无损传输的系统总体设计方案。设计了实现数据采集系统各功能模块的硬件电路，以及FPGA对系统各个模块的控制逻辑，并完成系统硬件测试和功能测试。测试结果表明本系统能够采集光电倍增管输出的微弱电流信号。     

基于RS-485总线的数据采集系统

基于RS-485总线的数据采集系统可实现对大坝坝体各方位的应变数据进行采集与数据处理。介绍了系统硬件和软件的设计,重点阐述了硬件电路中信号获取、信号放大、A/D转换、电源、通讯、数据存储以及时钟等模块的设计与实现方法。给出了系统的软件设计框图。     

发动机缸盖振动信号采集系统设计

基于LabVIEW图形化编程语言,实现了发动机缸盖表面振动信号采集系统的设计,该系统包括信号采集调理模块和LabVIEW虚拟仪器处理模块两部分。信号采集调理模块主要实现对采集到的传感器信号进行放大、滤波等信号调理,并把调理后的信号通过DAQ板卡输入计算机;LabVIEW虚拟仪器处理模块实现对DAQ板卡的驱动支持及通过驱动程序对板卡进行合理设置并对输入计算机的信号进行虚拟处理。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.