炮弹破片平均迎风面积测量系统研究

采用二十面体方法的迎风面积测量技术作为不规则形状的炮弹破片平均迎风面积的测量方法,并以此设计出了破片迎风面积测量系统,为下一步的典型破片初速测量提供重要参数。详细论述了系统的检测原理、总体结构及数据处理系统。通过实验对系统的测量精度进行了验证,系统的测量精度完全满足破片面积测量精度要求:±5%。     

空间坐标一致性光学测量方法研究

制导惯性装置的方位敏感轴与导引头CCD空间坐标一致与否直接影响导弹初始方位精度,介绍了一种导引头光轴坐标与惯性导航坐标安装误差的光学测量方法,阐述了此方案的原理、测量步骤,简要地分析了这种测量方法的误差。测量方案具有测量简便,调整快捷,非接触测量,测量精度高等特点,测量系统不确定度为±30″。     

一种铡草机实时喂入量的实验测量方法

本文介绍了一种铡草机实时喂入量的实验测量方法.文中给出了测量系统的工作原理和硬、软件系统的结构.实际测试表明该测量系统喂入量测试误差＜±13%.     

双纵模双频激光精密测距仪的研究

介绍了一种双纵模双频激光精密测距的工作原理,信号处理及误差分析。测距仪是以频差800MHz(对应波长长度为380mm)的波长为测量基准进行测量的,对不足半个波长的长度是利用双频激光干涉仪的原理进行测量的。对该测量方法精度的理论和实验研究后,可以确定出总的测量精度为±(50±1.5×10-6L)μm。     

基准环规检定和传递

内径环规基准件的检定至今仍是一个很伤脑筋的问题 ,因为希望环规的不确定度能保证在± 0 5μm范围内 ,而这样高的精度是很难达到的。表 1列出了在现有水平下测量环规直径所用的仪器及测量方法。表 1　测量环规所用仪器、方法和精度仪器名称规格型号测量方法 仪器精度μm卧式测长仪4J、JD5、JDY -1 0 0T -UIM -5 0 0、ZEISEOPTON绝对测量± (2 +L/1 0 0 )测量仪MUT -1 0 0 0、TJA相对测量± (0 6+9L/1 0 0 0 0 )象点反射比长仪 2 0 0型数字式比长仪直接测量± (0 5 +L/3 0 0 +H/1 0 0 )孔径测量仪 70 1A干涉比较测量± 0 5…     

一种高精度非接触位置测量系统

随着导弹技术的发展,位置测量设备的精度要求也不断提高.介绍位置测量系统的现状,研制出一种新的非接触位置测量系统,推导出新的测量方法--三角法测量技术原理,对某型号地空导弹发射车与装填车之间X,Y,Z,α的位置关系进行测量.通过三角知识及误差合成理论,分析出此系统的测量精度,长度(X,Y,Z):±1mm,角度(α):±3′.     

便携式接触网参数智能检测装置的设计及应用

在接触网的相关参数中,拉出值和导高是维护弓网关系的主要测量参数,传统测量方法由于工作效率低、对施工人员要求高等缺点,已经不能满足目前接触网参数测量要求。鉴于此,设计了一种采用激光雷达为主要检测装置,对接触网进行非接触式检测的软件系统。该系统的硬件部分以手推式小车为主要框架,安装有激光雷达、倾角仪、霍尔元件用于获取测量数据,然后由软件系统处理得到实时数据,并绘制出实时的导高和拉出值波形图,再导出所测量的数据,对于接触网的安全运营具有重要意义。     

入射角度变化对角锥棱镜测量精度的影响

为了掌握角锥棱镜用在激光跟踪仪中光束入射角度变化对其测量精度的影响规律。详细分析了角锥棱镜的工作原理和反射特性。计算出了角锥棱镜在不同入射角下的实际有效反射面积,并建立了角锥棱镜有效反射面积随光束入射角度变化的理论公式,进而得到角锥棱镜测量精度随光束入射角度变化的规律。实验结果表明：角锥棱镜测量精度随入射角增大而减小,在最大允许入射角处发生突变。在最大允许入射角±35.26°时其测量误差达到0.050mm;而在±20°范围内时其测量精度优于0.010mm,且入射角度在±15°范围内其测量精度最高,稳定性最好。所得结论证明了当角锥棱镜在入射角度为±20°范围内工作时能满足了激光跟踪仪的测量精度要求,这对角锥棱镜设计和实际测量工作具有指导意义。     

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。     

基于像差修正的同轴度测量方法

为了实现在同轴度测量中平行偏差(平偏)和倾斜偏差(角偏)两个量的同时测量,建立了基于激光准直性的光斑接收系统。该系统由接收物镜、分光棱镜和CCD构成。以物镜光轴、准直光束几何中心线和两个CCD接收面构成的三角关系进行两个偏差量的计算;并通过对系统像差的分析,提出了显著降低物镜像差对测量结果影响的算法。理论和实验数据表明,对于平偏测量范围为±10 mm、角偏测量范围为±2°、接收物镜焦距为50 mm、CCD尺寸为1.6 cm的系统,平偏测量精度可达0.02 mm,角偏测量精度可达9.5″。因此,该系统可以满足较大范围内的旋转机械同轴度测量的需要。     

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.