耦合型单模光纤传感器用于振动测量研究

讨论了一种以单模光纤耦合器的熔融区为敏感单元的耦合型单模光纤传感器。分析了该传感器的敏感机理,依据单模光纤耦合器耦合输出与耦合区长度和折射率的函数关系,提出该种传感器可实现振动测量。搭建了基于等强度悬臂梁的振动检测系统,通过与压电振动传感器的对比测试表明该传感器可更好地实现振动信号的测量,并分析了其振动响应特性。实验证明耦合型单模光纤传感器可以用于振动信号的测量。     

机器人触觉和热觉复合传感系统的研制

本文在分析现有机器人触觉、热党特点的基础上,提出了一种用PVDF做敏感材料研制的机器人触觉和热觉复合传感器的结构、硬件处理电路及其信号处理方法,最后,对研制的传感器及信号采集处理系统进行了触觉感知及热觉识别试验,给出了有关结果.     

低侧向效应MEMS压阻式加速度传感器

MEMS压阻式加速度传感器是目前最常见的测振器件之一。在某些特殊环境下,加速度信号组成较为复杂,例如机床主轴振动测试系统,可能有多方向加速度信号同时施加到传感器,这就要求设计的传感器具有较低的横向效应,即较小的横向交叉干扰,因此文中研制了一种可以从理论上消除传感器自身横向交叉干扰的MEMS压阻式加速度传感器。文中采用新型的复合八梁结构作为传感器的敏感元件模型,并利用敏感结构上的应力分布规律优化传感器的信号检测电路,从理论上消除了传感器的横向交叉干扰;通过MEMS加工技术加工了传感器的芯片结构,并进行了封装和相关性能测试实验。实验结果表明,所设计的传感器具有不超过1%的横向交叉干扰,1.798 m V/g的测量灵敏度以及14 kHz的固有频率。     

压阻式小量程SOI加速度敏感芯片设计与分析

为满足建筑物振动监测等应用对小加速度信号测量的需求,采用带有微梁和支撑梁的敏感结构设计了一种压阻式小量程加速度传感器芯片,为弥补压阻式传感器测量小信号精度低这一不足,基于SOI技术设计了单晶硅应变电阻.利用有限元法对敏感芯片结构进行了仿真分析,给出了兼顾灵敏度与固有频率这两个技术指标的设计方法,以此确定了敏感芯片的尺寸...     

SAW氢气传感器频率特性分析

基于ANSYS13.0建立了声表面波(SAW)传感器的三维有限元模型,选择金属钯膜作为传感器敏感薄膜,选用128°YX铌酸锂作为基底材料,输入和输出叉指电极(IDT)耦合在基底表面。给输入IDT施加单位阶跃信号,并对所得到的时域响应数据进行傅里叶变换得到传感器的中心频率和插入损耗。将仿真所得频率特性与实验结果进行对比,得到了可以降低插入损耗、提高传感器性能的方法。     

基于磁敏测量技术的拉线式位移传感器

基于磁敏感角度测量处理器MLX90316开发了一种拉线式位移传感器。分析了拉线位移传感器的测量原理并推导了拉线位移与滚轮角度的解析关系。基于Cortex ARM处理器,设计了位移传感器的角度信号采集和信号输出电路;完成了传感器的整机机械结构设计。开发了位移传感器的应用软件,具有参数设置、传感器标定及符合标准Modbus协议的通讯等功能。试验表明:拉线式位移传感器测量精度能达到0.02 mm,性能稳定,可满足工业领域对位移测量的需求。     

大容积钢制无缝气瓶压扁试验测速系统设计

本设计主要完成大容积钢制无缝气瓶压扁试验压头速率的测量。在压扁试验机上安装光栅传感器,光栅传感器与试验机压头同步移动。随着试验机压头的移动,光栅传感器给出脉冲信号井传送给计数器,由计数器完成脉冲信号到计算机能够识别的ASCⅡ码的转换并通过RS232接口将信号输入计算机,计算机对该信号进行解码并处理得到实际光栅传感器的实时速率,并最终显示在显示器上。     

基于敏感分量融合的液压泵退化特征提取方法

液压泵退化特征提取是实现故障预测的关键环节。在液压泵性能退化过程中,其振动信号复杂度高、非线性强,难以有效地提取退化特征,为此,本文提出一种基于敏感分量融合的退化特征提取方法。采用改进局部特征尺度分解(ILCD)方法对振动信号进行分解,并利用贝叶斯信息准则与所构建的敏感因子,对内禀尺度分量进行筛选,以减少干扰分量的影响,得到敏感分量,有效抓取特征信息;在此基础上,引入离散余弦变换代替传统复合谱分析中的傅里叶变换,提出离散余弦变换-复合谱(DCS)算法,以解决信息遗漏问题,并利用DCS对敏感分量进行融合,提取复合谱熵作为退化特征,以提高对退化过程的表征能力;最后,通过对液压泵性能退化试验实测振动信号的应用分析,验证了该方法的有效性。     

透光脉动颗粒传感器的研制与应用

详细分析了基于透光脉动技术的透光脉动颗粒传感器的检测原理，理论分析表明，该传感器的检测信号完全不受取样管管壁的粘污以及电子元件老化、漂移等不利因素的影响。介绍了检测信号的处理方法并完成了该传感器的制作。利用该传感器对水中胶体颗粒物质絮凝过程进行了动态监测，对饮用水中病原体微生物进行了检测。实验研究表明透光脉动颗粒传感器能有效的对水中颗粒物质进行在线连续检测，无论是在实验室研究还是生产应用中都极具实用价值。     

基于PSD技术的位置自动检测系统

介绍一种以位置敏感器件(Position Sensitive Detector，PSD)为核心构成的位置自动检测系统。概述了光电位置传感器的工作原理和特点，分析了输出信号与位置参数的关系．论述了信号和数据处理系统的硬件组成与软件功能．并给出了系统的主要参数。     

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.