基于FIFO写数据方式的USB接口信号发生器设计

介绍了一种USB接口虚拟仪器,该虚拟仪器采用FIFO写数据方式作为信号发生器的数据传输模式。信号发生器使用EZ-USB系列USB芯片CY7C68013作为硬件的主控芯片,上位机利用VC++设置程序实现波形的产生,产生波形信号后,调用cyioctl控制函数与下位机固件程序完成数据的通讯,最后由固件程序实现对内部FIFO芯片存储器的读写。     

软硬结合的方法实现PLC与DCS的时钟同步

不同控制系统的时钟同步一直是自动化行业的一个难题,以西门子S7400和PKS300系统为例,对比不同方式实现系统时钟同步的优缺点,重点介绍了软硬结合自动定时校正的方法实现系统时间同步的方法。以DCS为主时钟源,每天定时向PLC系统发出校时脉冲信号,该信号通过硬线传输。PLC系统接到信号后通过软件设置将系统时间调整为指定时间,这个时间就是DCS发送脉冲信号的时间,从而实现PLC系统与DCS系统的时钟同步。通过这种方法将聚丙烯装置中的各个PLC系统与DCS主系统时钟同步。     

基于光信号的电火花线切割数据采集系统研究

针对电火花加工过程中利用电压、电流波形等电信号对放电间隙状态监测存在的易受干扰等不足,提出了一种基于放电火花光信号图像的信息采集方法与控制系统.该系统包含机床硬件与控制、数据采集及上位机控制程序等模块.以STM32开发板为控制内核,通过RS232与上位机通讯,实现机床电器控制;以Hispec高速摄像机与NI6366数据采集卡为时钟同步采集装置,分别通过TCP/IP协议及USB总线与上位机通讯,实现电火花放电图像和放电间隙电压和电流信号的同步采集;在此基础上,以PC机为上位机,运用LabVIEW软件,设计了采集界面及控制程序,实现机床的实时控制、采集数据的保存、回放及分析处理等功能.实验分析结果表明,通过分析处理空载脉冲、正常脉冲及非正常脉冲等不同放电状态下的采集数据,可有效识别放电间隙状态,为利用火花图像特征建立放电状态的预测模型提供了一种新思路,从而为高效的多槽电火花线切割中的解耦控制问题提出解决方案.     

基于虚拟仪器的手绘任意波形发生器

采用虚拟仪器技术,设计一种新颖的任意波形发生器.系统通过Visual Basic的界面编程,实现上位机手绘波形并记录波形数据,并以Visual C++进行底层USB数据的控制和传输.记录的波形数据经过USB传输到C8051F320,再由D/A电路转换,最终完成波形输出的功能.试验证明设计的任意波形发生器能够实现上位机任意手绘波形的对应输出,配置灵活、使用方便.     

基于VB的虚拟数字存储示波器

利用P8xC591内部的AD转换器实现对被测信号的采集,以串行通信的方式传送到上位机,并通过上位机程序实现被测信号波形的实时显示、存储和回放。     

用XC4000系列芯片设计同步FIFO存储器

本文描述基于双口RAM的同步FIFO存储器设计。双口RAM是采用可编程逻辑XC4000系列器件中的双口RAM,同步FIFO设计使用公共读/写时钟信号。     

列车轴温探测器监测系统的设计

为了使列车轴温探测器在出现故障时能够及时通知值班人员,设计了一种基于ARM的监测系统。该系统由监测仪和上位机两部分组成。监测仪实时采集线路电压波形并通过快速傅利叶变换等数字信号处理方法分析信号的失真度和幅值,利用FSK芯片解码报文来计算轴温探测器的误码率,当发现故障时将其存入U盘并通过调制解调器传给上位机,监测仪还具有自检、记录断电时间等功能。上位机能够从调制解调器和U盘获得故障信息并利用ODBC数据库进行统计管理。该系统已经投入使用,运行状况良好。     

车轮踏面裂纹检测系统中数据采集电路的设计与应用

针对裂纹检测系统中EMAT回波信号的采集,设计制作了相关的硬件电路。采用EPP并口模式对电磁超声数据进行采集,采集卡选用AD9057作为A/D采样保持转换器以及IDT公司推出的先进先出(FIFO)存储器芯片;系统时钟采用一片74LS74进行分频以实现频率可调,供给AD9057采样脉冲和IDT7203写FIFO脉冲;延时外触发电路采用最外一个触发VMOS管的信号,接入一个74121单稳态触发器中,延时后触发FIFO复位信号;采样频率设定为5 MHz。完成数据采集电路的调试后,用于实验室钢板裂纹信号检测,可以观察到频散的板波波形。结果表明,设计开发的EMAT数据采集卡能够成功地接收到由于遇到缺陷而引起衰减的回波,可以有效地检测出裂纹。     

基于FPGA的USB虚拟示波器

介绍了一种基于FPGA和AD9224的USB虚拟示波器,该系统用AD9224实现模数转换;用FPGA实现多路开关、可变增益放大器、A/D和D/A的逻辑控制和内部FIFO高速缓存读写;控制D/A转换器实现自动换档;并通过直接控制CY7C68013A芯片实现采集板与上位机之间的USB数据传输;利用LabVIEW编写了上位机示波功能界面.该虚拟仪器系统实现了信号的采集、存储、传输、显示及信号处理,经实验测试性能稳定,能够满足便携性要求.     

TMS320VC5402与CY7C68013的接口设计

介绍了一种利用CY7C68013的通用可编程接口（GPIF）访问TMS320VC5402内部存储器的方法。应用Cypress公司开发的GPIF波形设计器设计了用单字节写方式控制主机接口（HPI）内部寄存器、用FIFO读／写方式读／写DSP内部RAM的3种控制波形,并在此基础上着重分析了读／写DSP内部RAM的GPIF波形时序。最后,介绍了相应的固件程序设计和设备驱动设计,并把该方法应用于信号发生器输出信号的采集,验证了该方法的可行性。     

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.