现代测控平台动态测试系统研究

利用已有设备 ,以通用的 D/A、A/D转换和数据 I/O卡为硬件 ,以振动台、功率放大器、电荷放大器、信号发生器等设备产生信号 ,结合虚拟仪器概念与技术 ,组建了一套完整的动态测试实验系统。该系统可以进行动态信号采集与处理 ,可对动态信号进行多种信号分析。同时结合虚拟仪器技术开发了便于应用的用户界面。在开发系统的同时 ,还对一些动态信号分析方法作了深入研究     

热连轧机液压压下系统的动态测试系统的研究

热连轧机液压压下系统的时域和频域特性直接影响整个轧机的性能，因此必须进行液压压下系统的动态测试。用加载缸模拟负载的方式，通过自行设计的电路对磁尺信号远距离传输，采用Visual Basic和Borland C＋＋混合编程方式实现攀钢1450热轧板厂HAGC液压压下系统的动态测试。该测控系统控制精度高、抗干扰能力强，操作方便，可用于其他液压系统的动态测试。     

基于嵌入式系统的便携式心音分析仪的研究

心音作为一种人体重要声信号，在心血管疾病研究中具有重要价值。本研究开发了一种基于嵌入式计算机、用于采集并分析心音信号（PCG）的便携式辅助诊断系统，实现了以下功能：心音及同步心音信号的双通道采集，准确实现心音定位；病人信息和心音数据的数据库管理；心音信号波形回放及声音回放。更为重要的是，该系统能对心音和心杂音进行能量和时频特性分析，获取心音信号的时频特征，对心脏病进行辅助诊断。该仪器体积小、成本低、使用灵活方便，特别是对一些因患心脏疾病而不方便行动的病人可实行床旁动态监护。     

一种大动态范围数字式智能微伏表的设计

本文提出一种用于测量大动态范围变化的弱信号的方法,经实际测试,取得了满意的效果。该方法采用以增益可控部件为核心的步进式数字自动增益控制电路,对信号进行大范围动态压缩;利用８０Ｃ３１微处理机对信号进行实时处理,使系统完成实时显示、故障自检和过载自动报警等功能。它既可作为大动态范围数字式微伏表,又可作为多通道大动态范围低噪声放大器使用。本文主要介绍了系统的基本工作原理、系统的硬件结构及主要软件流程。     

APPLE—Ⅱ微型机在线信号处理系统通过鉴定

华中工学院机械工程一系研制的APPLE—Ⅲ微型机在线信号(动态数据)处理系统已于八四年八月二十四日在华中工学院通过鉴定。该系统是以APPLE—Ⅲ微型机为基础,附以信号采集和外围设备,以及成套软件构成的多功能信号(动态数据)处理系统。该系统可在线/离线对连续信号(动态数据)进行采集、分析和处理。目前,以微型机为基础的在线信号(动态数据)处理系统是信号处理系统发展的趋向。但是,国内外尚无能进行现代时序分析处理的信号处理系统。该系统的研制,使微型机不仅具有直接在线完成传统的FFT方法的分析功能,而且能直接在线用时序方法处理动态数据,是一种完整的动态数据分析     

用于智能蒙皮的集成化动静态测试系统设计

研制了一种用于机翼智能蒙皮结构的多路动静态信号测试系统，完成了该系统的软、硬件设计，深入研究了系统设计中的关键技术及电路的抗干扰问题。该系统可采集多路静态应变和动态振动响应信号，且集成了电荷放大器、应变测试仪、示波器、FFT分析仪及数据存储器等功能，可用于航空航天、机械工程、医疗卫生等领域。系统精度高，抗干扰能力强，稳定可靠且长时间运行状态良好。     

动态称量信号的采集与分析处理系统

本文介绍一种可对动态称量信号进行采集与分析处理的系统软硬件构成及主要功能特点，并给出其应用及结果分析。     

系统动态校准中输入阶跃信号过渡时间参数分析

分析了阶跃信号过渡时间参数对动态校准结果－系统频率响应函的影响，得到了系统频率响应函数误差与过渡时间参数误差的关系，最后对典型的斜坡型负阶跃信号进行了分析。本文对采用阶跃信号动态校准系统的误差分析具有重要的意义。     

压电式加速度传感器在振动测量系统的应用研究

压电式加速度计具有体积小、质量轻、测量范围宽等特点，在振动测量系统中得到广泛应用。分析了压电式传感器作为一种机电换能器，将振动加速度转变成为电量进行测振的具体原理；阐述了基于压电式加速度计构建振动测量系统的总体方案，整个测试系统主要由压电式加速度计、电荷放大器、动态信号分析仪组成，采集所得振动信号可以实时显示、存储、分析和处理。最后，将该系统应用于压路机实际测振进行了验证。     

基于LabVIEW的橡胶动态特性的测试系统研究

根据橡胶动态特性的测试要求,设计了一套集数据采集、分析、处理与显示于一体的虚拟测试分析系统,实现了对试验数据的实时处理和输出结果的可视化.该系统在数据处理过程中可自动修正误差,提高了试验结果的可靠性.该分析系统采用了DAQPad-6070E高速数据采集装置对超弹性橡胶材料的动态试验信号进行采集,通过1394数据卡建立了采集的数据与基于LabVIEW软件设计的数据分析系统的动态链接,并运用LabVIEW7.0虚拟平台的强大模块功能对试验数据进行分析处理,得到了橡胶材料的动态特性曲线.     

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.     

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....     

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。     

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.