短距离无线数据传输系统的设计实现

介绍了一个基于nRF2401A射频芯片的短距离无线数据传输系统,通过AT89C52单片机控制射频芯片nRF2401A,实现2个射频芯片之间在ShockBurstTM模式下进行数据的发射与接收,同时接收方通过AT89C52单片机的串口将接收到的数据经RS232接口电平转换后传给主机.通过实验分析了无线数据传输系统的性能、主要影响因素以及系统的稳定性.     

加速度传感器静态标定数据无线采集系统的设计

在传统加速度传感器静态标定设备的基础上,设计了一种无线数据采集系统.该系统以低功耗射频芯片CC2430为硬件核心,LabVIEW 8.20为系统软件开发平台.加速度传感器产生的电压信号经过无线收发模块中CC2430内部A/D采样,通过天线发送出去;与PC机相连的无线收发模块接收到数据后,通过USB口传输数据.系统具有功耗低、安装简便、数据存储和显示等功能,简化了数据采集过程,提高了采集效率.     

基于CC2420和ADXL330的无线传感器数据采集系统

研究基于无线传感器网络(WSN)的数据采集系统.简要介绍了ZigBee技术协议以及CC2420和ADXL330的性能和特点,设计了一种基于CC2420和ADXL330的无线传感器数据采集系统,给出了具体的软、硬件设计方法.该系统选用高灵敏度的三轴加速度传感器芯片ADXL330来采集管道破坏时产生的振动加速度信号,通过支持ZigBee无线传输协议的CC2420把数据发送给接收装置.     

利用无线模块的列车轴承在线监测系统的设计

鉴于道旁麦克风采集的声音信号受多普勒效应及周围噪声影响而难以提取的缺陷,提出一种基于无线模块的轴承在线监测系统。通过振动传感器在线采集轴承振动信号,利用无线模块进行无线数据传输,最后对接收到的数据进行分析处理以确定是否有故障。主要从无线模块选型、硬件电路实现、通信协议等几个方面介绍了系统的设计与实现过程。     

无线传感器网络振动信号采集节点的设计

针对目前无线传感器网络节点采集旋转机械振动信号存在的高成本和大功耗问题,设计一种基于CC2530芯片的无线传感器网络节点。该节点采用数字式三轴加速度传感器拾取振动信号,以CC2530自带处理器为整个节点控制核心,将采集、存储、处理和传输等控制功能模块集成到一起,实现振动信号的准确采集和大数据量存储,并成功移植Zig Bee协议栈,实现数据的无线传输。经测试表明:该节点对于信号采集和无线传输具有较高的可靠性和稳定性,能够满足大多数旋转机械设备的振动监测要求。     

基于嵌入式可燃气体报警系统设计

基于射频芯片Si1000和嵌入式芯片AM3352设计的可燃气体无线报警系统,具有结构简单、响应速度快等优点。该系统采用高性能ARM8芯片,通过芯片内部集成了高精度A/D实现数据的采集,通过短距离无线射频模块快速发出报警信号。经实验测试,该系统性能稳定,能准确检测出可燃气体并发出报警信号。     

螺杆式空压机故障诊断

本文通过螺杆空压机振动的频谱分析,排除阳阴转子、电磁振动等故障。从位移、速度和加速度频谱分析,诊断螺杆空压机主机轴承损坏和电机地脚螺栓松动的故障,从中总结出旋转机械常见振动故障的诊断方法。     

基于nRF905的温度数据无线采集系统的设计

设计了一种由单片机SPCE061A和射频芯片nRF905模块所构成的嵌入式温度数据无线采集系统。介绍了系统的具体工作流程,给出了无线数据采集部分和无线主机部分的硬件结构逻辑框图。在软件设计上,采用了C语言编程,并在此基础上给出了射频芯片的工作流程,最终实现了嵌入式的数据无线采集系统的设计。     

基于nRF24E1的便携式箱包防盗装置

本文介绍了基于2.4GHz无线射频收发芯片nRF24E1的短距离无线防盗装置的设计,着重介绍利用这款芯片的特点构建一个低成本、高可靠性、便携式箱包防盗装置的解决方案.本系统可以实现距离报警和振动报警.     

基于87C196的便携式滚动轴承检测与诊断系统

滚动轴承是旋转机械设备运行过程中的重要元件,也是旋转机械的薄弱点,轴承的质量及损坏磨损程度将直接影响旋转机械的运行状况,据统计旋转机械的故障约30%来自于轴承,因此对轴承状态的检测显得极为重要,这也正是本文的主要出发点.本文对轴承的状态检测与诊断主要采用基于振动信号频谱分析的方法.系统利用加速度振动传感器对振动信号进行提取、放大、滤波,再将信号输入Intel 87C196单片机、为微处理器的便携式系统中进行存储、处理,或者通过RS-232串口将数据上传到微机,利用相应的振动测试分析软件对信号进行分析处理.通过对振动轴承的频谱分析,可以方便快捷的了解轴承的运行状态,以防止故障与事故的发生.     

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.