适用于PEBB采样系统的高速光纤隔离通讯装置

为了解决系统中较高电压电流变换率对采样产生的干扰问题,提出一种基于现场可编程门阵列(FPGA)的光纤隔离采样通讯装置,并阐述了该装置的具体设计思路及步骤.这种装置可实现信号采样并进行数字化传输和接收,具有优良的绝缘性能和暂态特性,对复杂电力电子系统隔离采样及信号传输有工程实用价值.最后通过实验给出了两个节点间数据传输波...     

面向低压电网的高精度电量测量装置

设计了一种基于超低功耗MSP430F149为核心的高精度的电量测量装置,该装置由硬件电路和控制软件来共同实现.主要阐述了系统的信号采样、信号隔离及防雷击过电压电路的设计,交流采样和数字滤波的算法,并实现了ModBus-RTU协议下的远程通信等内容.应用结果表明该装置满足工业级的需求,运行稳定可靠,通用性好,测量精度高,具有很强的实用性和推广价值.     

基于FPGA的模数转换芯片MAX191控制器的设计

M AX191是M AXIM公司生产的低功耗、高速度、高精度的12位AD转换器,采用型号为EP4CE6E22C8的FPGA芯片对M AX191进行实时采样控制,并将采集到的数据通过RS232发送至分辨率为(800×400)像素的LCD上实时显示.整个设计过程采用硬件描述语言Verilog在EDA平台QuartusⅡ14...     

高速ADC交叉采样控制器的FPGA实现

设计了2通道和4通道高速ADC交叉采样控制器,可以把采样速率分别提高到2倍和4倍.对高速ADC,使用CPU无法满足速度要求,所以使用FPGA实现控制.控制器使用了FPGA片内锁相环产生具有等相位差的采样时钟、输出时钟和控制信号,对输入的ADC交叉采样数据进行交叉处理,然后输出合成的高速采样数据.仿真结果表明,这种交叉采样的控制算法是可以实现的.     

基于锁相放大原理的微弱信号检测装置的研制

为解决传统信号检测装置精度低、信噪比低的问题,研制了一种基于锁相放大原理的微弱信号检测装置。本装置是以超低功耗单片机MSP430为处理器,结合锁相放大原理实现的微弱信号监测装置,该装置包含加法器、纯电阻衰减网络、微弱信号检测电路及单片机控制显示和AD采样。本装置能将微弱信号从强噪声中检测出来,并通过液晶显示实时采样的幅值,且误差最高能达到1%以下,所能检测到的弱信号幅度能达到20mV以下,误差基本能达到要求指标。     

基于FPGA的等效采样存储示波器设计

提出了一种应用于便携式数字存储示波器等效采样的实现方案.详细讲述了FPCA和微处理器LPC2138对高频信号随机等效采样的处理过程,利用一种全新的方法即主要利用FPGA内部逻辑单元完成对触发时刻到与下一采样时刻的时间间隔的测量.给出了FPGA对采样点的处理方法和LPC2138数据的处理及波形还原的软件处理过程.实现一个模拟带宽为1Hz～100MHz的手持式数字存储示波器.     

便携式交流电量变送器检测仪

提出一种以TMS320F2812 DSP芯片为核心的便携式交流电量变送器检测仪的软硬件设计方法.介绍了交流电量算法原理及系统结构,给出了低功耗ADS8320和LTC2400等器件构成的交直流检测电路、准同步采样电路和主程序流程.详细介绍了功率校正方法,解决了附加相位引起的功率测量误差.实验表明该装置精度达到0.2级且功耗低,体积小,符合便携要求.     

基于ARM&FPGA的CCD图像识别装置

给出了一种CCD图像识别装置的设计方法,该装置以ARM与FPGA为主控芯片,设计了基于Nios Ⅱ的A/D控制模块并行控制多路CCD图像信号的数据采集和基于Nios Ⅱ的多种内核,重点介绍了基于Nios Ⅱ的LCD驱动以实现液晶显示、设计A/D采样控制模块以实现多路数据采集以及设计SL811HS驱动以实现ARM与PC的USB通信等.实验结果表明系统具有应用价值高、速度高、可靠性高、故障少等优点.     

适用于新型智能机器人的高性能低功耗视觉系统

根据新型智能机器人的工作使命和作业特点,设计了一种适应性强、针对性好的高性能低功耗视觉系统.该视觉系统选用TMS320DM642作为核心处理芯片,负责处理复杂的算法,底层图像处理系统选用Altera Stratix Ⅱ系列FPGA,利用FPGA配置硬件器件和处理底层数据.DSP和FPGA采用两帧轮换的数据存储方式,具有处理速度快、可扩展性好的优点,能够提高视频图像的运算和处理效率,能够满足新型智能机器人对视频图像进行实时处理的要求.     

基于FPGA的机械振动信号采集和以太网传输的实现

提出一种基于FPGA的机械振动信号数据采集和以太网数据传输的设计方案,利用VHDL语言编写软核,在FPGA内部实现采样控制、数据缓存、数据封装以及以太网通信控制,通过实现变频率采样解决机械振动信号测点多样的问题。实现一个专用CPU解决FPGA和以太网适配器DM9000的接口控制。     

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.