具有多种输出方式的风向传感器设计与实现

为了增加风向传感器的使用灵活性,本文设计了一种可配置为电流或电压输出的风向传感器。该传感器利用单片机采集风变换器数据,并可以控制输出电路输出4-20mA电流信号、0-20mA电流信号、0-5V电压信号、0-10V电压信号中的一种信号。该传感器具有性能可靠、精度较高、使用灵活等优点,可以广泛用于各行业的风向测量。     

基于VCSEL半导体激光器的浊度传感器设计北大核心CSCD

为更准确测量水体的水质浊度,设计一种基于半导体激光器的浊度传感器,该传感器由光学采集模块、信号处理模块、信号输出模块和电源供电模块组成。光学采集模块采用850 nm的VESEL半导体激光器为光源,采用后向散射光检测法,该方式具有宽线性范围,适用于悬浮颗粒物浊度测量。信号处理模块采用I/V转换电路、滤波检波电路、三级运放电路、振荡电路、温度补偿电路和差分放大器对采集的散射光信号进行处理。信号输出模块采用放大电路和4~20 mA转换电路将散射光信号转换成4~20 mA信号。传感器性能测试结果表明:浊度传感器准确度误差在±1.36%以内,稳定性优于0.6%,具有较高的准确性和可靠性。     

基于DSP的智能隔离检测系统的设计

研制了一种基于DSPTM320LF2407A的线性光耦隔离智能检测装置，具有对16路模拟量（0-5V电压信号或4～20mA电流信号）和4路开关量进行隔离采集、处理、显示以及故障报警的功能。使用低成本的线性光耦，隔离模拟信号输入；采用滑动平均滤波技术，对输入信号进行滤波，以获得真实输入信号，并对超越阀值的信号进行报警显示；采用异步串行通信方式，通过RS-485接口，与计算机进行近地、远地通信，实现对被测系统的实时监测。     

MPC-10可编程序控制器

MPC-10可编程序控制器由机械电子部北京机械工业自动化所研制成功,并小批量投产。该控制器主要用以完成开关量的逻辑运算,进行计时、计数、分支程序、子程序的控制。并具有数字运算、数值处理及模拟量闭环调节等功能。其主要技术参数为:①I/O开关量64～128/64～128,光电隔离,固态继电器输出,并可根据需要扩展;②模拟量输入16路,10位0～10mA,4～20mA,0～5V,1～5V线性光电隔离,可     

新型小信号模数转换表的研制

新型小信号模数转换表用于电力小信号模拟量的测量,可手动设置模拟量电压或电流的对应量,并将其对应量数字显示,避免手动计算的繁琐,提高工作效率。采用高精度的电流/电压传感器,能快速感知主变油温、主变绕阻温度;转换表含小信号模拟量(4～20 m A、0～5 V、0～10 V)对应温度示值处理单元,可在强电场、强磁场的复杂电磁环境下,确保小信号模拟量快速采集时不失真。     

基于两点校准的模拟量输出现地装置设计

该文基于国产处理器芯片设计了一款模拟量输出现地装置,该装置提供4路0～5 V电压输出及4路4～20 m A电流输出。阐述了该装置两点校准实现过程,搭建实验验证平台,实验结果表明,该方法能够满足全量程校准要求,改善模块输出精度。该研究为提高模拟量输出现地装置精度提供了参考。     

Y98-1000/46X25型研配试冲液压机下拉伸垫压力闭环控制

介绍了采用西门子S7-300系列PLC,CPU单元选用CPU317-2DP,模拟量输入模块选用6ES7134-4FB51-0AB0,模拟量输出模块选用6ES7 135-4LB02-0AB0,由HM13型压力传感器检测各个油缸的压力值,通过模拟量输入模块反馈给CPU进行控制计算,控制模拟量输出模块输出电压值驱动比例伺服阀,开发了PID压力调整补偿程序,实现了下拉伸垫拉伸力的闭环控制。     

核电厂安全级DCS模拟量隔离器的设计与研究

核电厂安全级DCS系统中有温度、压力、流量等数量较多的模拟量信号,变送器将现场传感器采集的非标准电信号转换为4mA~20mA标准信号送入系统进行模拟量数字化处理。针对核电厂安全级DCS系统的隔离和分配要求,需要一种高性能的模拟量隔离器对4mA~20mA模拟量信号进行隔离和分配。提出了一种基于线性光耦的核电厂安全级DCS模拟量隔离器的设计方案,通过对电路的原理设计以及器件的选型,使得该方案具有电路简洁、精度高、温漂小、响应时间短、制造成本低等优势。该模拟量隔离器在核电厂安全级DCS系统中具有广泛应用。     

一种功能安全的模拟量输入卡设计

4～20 mA是工业最常用的模拟量输入,功能安全的模拟量输入卡通过2oo3电路比较,更准确地保证仪表的安全使用。介绍了一种功能安全的模拟量输入卡,其三套采样电路都各自带有开路、短路等自诊断功能,通过模拟开关控制输入是采样信号还是用于诊断信号黏连的DA模块输出步进码值;AD模块把模拟量电压信号转换成数字信号进入MCU处理,MCU和FPGA通过并口进行数据交互。FPGA再通过RS-485把采样处理的数据传输到MPU。同时把采样后端处理电路和前端采样电阻、保护器件分别置于两块板子上,提高抗干扰能力。     

双柔铰导向式双足压电直线电机的驱动电源设计

为了实现双柔铰导向式双足压电直线电机连续和步进2种作动模式,电机的驱动电源需要产生不同类型的驱动信号,并且通过改变驱动信号的幅值或频率可以改变电机的运行速度。根据该驱动要求采用嵌入式微处理器PSoC作为信号发生单元,应用直接数字式合成器技术产生3种模式的4路驱动信号,利用LM358构成的两级电压放大电路,再通过IRF630构成的功率放大电路对信号进行电压与功率放大。实验表明,该驱动电源能够输出不同模式的信号,输出电压幅值调节范围为0~120V,频率调节范围为0~2kHz,能够实现电机的工作模式、运行速度与运行方向的调节。     

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.