一种便携式测温仪的研制

介绍了利用数字式温度传感器DS18B20构成的多点温度测量仪器.它具有线路简单,测量精度高的优点(在0～+45℃内,精度优于0.2℃);带有计算机接口,能够实现长时间连续测量与记录.     

面对面垂直度测量的误差分析与修正

阐述了用三坐标测量机测量面对面垂直度的原理,分析了影响测量精度的主要因素。采用最小条件法拟合基准平面,以减小基准平面拟合误差;准确测量被测平面内一段长度,按比例放大至整个平面,以减小被测平面长度误差;通过大量实验和对比分析,确定用等间距法测量平面的最佳采点数,以减小采样误差。     

3204B型齿形齿向测量仪的设计

齿形齿向测量仪是齿轮制造业广泛使用的一种精密齿轮量仪 ,它可通过一次装夹工件完成对齿轮或齿轮刀具渐开线齿形误差和螺旋线齿向误差的测量。我厂研制的 32 0 4Ｂ型齿形齿向测量仪采用基圆分级式原理测量渐开线齿形 ,利用仪器随带的一组(13个 )基圆盘并借助简单的基圆盘调整补偿机构 ,可实现规定范围内任意基圆半径工件的齿形、齿向误差测量。该型号齿形齿向测量仪配备了计算机及专用测量软件 ,可对测量数据进行自动处理与计算 ,并可在计算机屏幕上实时显示误差曲线及误差数据并打印输出测量结果。　　1　仪器测量原理(1)用专用基圆盘测量…     

汽车ESP和EPS系统的转角转矩组合式传感器

对一种可用于汽车ESP和EPS系统的转角与转矩组合式非接触传感器进行了研究.介绍了该传感器的结构和原理,推导了传感器的输出方程和灵敏度表达式.通过试验分析了传感器激磁磁场强度对转矩测量精度的影响,并得出了最佳激磁磁场强度.在0 ～450 N·m范围对传感器进行扭矩加载,得到了较高的测量灵敏度、线性度、重复度以及较低的迟滞静态误差;在500～3500 r/min范围内,转速最大相对误差为0.80％.试验数据显示:该传感器的精度能够达到1.0％,用于测量汽车方向盘的转矩和转角是可行的.     

探空温度传感器的太阳辐射误差修正方法研究

由于太阳辐射的影响,探空温度传感器高空测量时的辐射误差可达3 K量级。为提高传感器测量精度,提出一种太阳辐射误差修正方法。首先通过计算流体动力学(CFD)方法计算珠状热敏电阻的太阳辐射误差,然后采用准牛顿法(BFGS)拟合仿真数据并得到太阳辐射误差修正方程,最后通过低气压风洞和太阳模拟器实验平台对修正方程的准确性进行验证。实验结果表明,在太阳高度角和海拔高度范围分别为0°～60°和10～32 km时,珠状热敏电阻辐射误差修正值与实验测量值之间差值的平均值为0.124 K,均方根误差为0.083 K,验证了辐射误差修正方法的可行性。     

基于光强可调的浊度智能检测传感器研究

为了使浊度传感器量程与精度调节智能化,基于光学检测浊度的原理,研究了溶液透射光检测电压和入射光强的非线性变化规律,建立了电压差-浊度间测量模型。设计了通过PWM占空比调节不同溶液间的电压差改变量程与精度的传感器,进行了量程1(1～1 000 NTU)和量程2(0～200 NTU)的实验。实验结果显示,在量程1时,重复性误差为1.7%,示值误差为10%;在量程2时,重复性误差为1.0%,示值误差为4.5%。结果表明,测量低浊度时,量程2精度更高;测量高浊度时,量程1范围更大。实验证明了该模型的可行性。     

激光追踪仪的基本原理及应用

介绍了激光追踪仪(Laser Tracer)的工作原理、结构特点以及误差修正方法。在工作原理方面,内部的激光干涉仪测量出Laser Tracer与安装在数控装备运动轴上靶镜之间位移的变化量,来对数控装备的运动误差进行计算。在结构特点方面,通过使用标准球反射镜与万向节式回转轴系,减小系统误差对测量精度的影响。在误差修正方面,利用多基站下的全球定位系统(Global Positioning System,GPS)原理确定各基站在数控装备坐标系下的坐标,并通过对数控装备运动误差的计算,分离出每一根轴的各项几何误差,同时合成数控装备在空间任意位置的误差,从而实现对数控装备误差的修正。     

基于误差理论的机床上导轨精度测量与分析

介绍了机床内防护上导轨位置度检测装置的机械结构及设计原理,结合误差理论,深入阐述机床内防护上导轨精度测量与误差分析,通过测量与分析理论建立,为机床导轨精度检测提供研究基础。     

基于纳米晶软磁合金的转矩、转速和转角多功能传感器研究

为提高传感器的多功能性,对一种可同时测量转角、转速和转矩的非接触式传感器进行了研究。首先,论述了传感器的结构和基于纳米晶软磁合金压磁效应的测量原理,然后推导出传感器的输出数学模型与灵敏度表达式。最后,在25～100℃温度范围、0～450N·m转矩范围及500～3525r/min范围内进行试验,得出相对于25℃的零点温度漂移为0.002 03%/℃(满量程),满量程最大线性度、重复度及迟滞静态误差分别为0.81%、0.50%、0.85%,转速最大相对误差为0.70%。试验数据还显示,该传感器的测量灵敏度为1.26mV/N·m,精度达到1.0%,对于一般工程应用是可行的。     

高精度不可见内回转曲面在线自适应测量

本文介绍一种测量精度为± 2微米的高精度计算机辅助二维在线测量系统的测量原理和方法。分析了系统精度 ,用双频激光干涉仪测量系统组成部分的误差 ,并通过软件方法进行补偿。用最小二乘原理对燕尾榫槽轮廓度加工误差进行误差分离和测量信息反馈 ,Minimax方法对轮廓度加工误差进行最优计算。     

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.