激光在精密测长和几何形状精度测量中的应用

<正> 一、序言超精密测长或精确定位的激光干涉装置,由于频率稳定的双频激光器问世,大大增加了其实用性。近年来,作为工业领域中一种实用的光学精密测量仪得到了迅速的发展。激光干涉装置的测长精度,取决于激光波长的稳定性。最新颖的装置,可与物理标准相匹敌,达到±0.1ppm。即一米长度的测量精度是±0.1μm。由于其重复性好,给人类提供了高精度、高稳定的长度和比较标准。     

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。     

双频激光光源技术研究现状与进展

双频激光的波长稳定性及频差大小直接影响激光干涉仪的测量精度及测量速度,因此高性能双频光源对激光干涉仪的测量至关重要.介绍了近20年双频激光技术的最新进展,比较了实现双频输出的不同方案,如塞曼分裂、双折射及声光调制等,简明阐述了不同双频激光器的原理、特点及应用场合,对其光学分离方式、频差大小、安装难度及结构成本等特性进行...     

用激光和CCD测量大型工件外径

大型工件的外径(一般指大于500mm),其高精度测量一直是我国机械行业中普遍存在又需要解决的共性难题。激光技术在长度测量方面,已得到比较成熟的应用。在生产车间环境下,双频激光测长仪相对测量精度可达10~(-7)mm以上。目前汽轮机行业提出的测量要求是:测量范围1～4.2m,测量精度±3×10~5D(D为被测直径),可见用激光技术完全可以满足大直径测量中的长度测量的精度要素,其关键是如何准确地捕捉直径上的两个测量点,即准确地定位,从而把直径测量转换为单纯的长度测量。本文从实用化的角度,提出一种大型工件外径的测量方法,用准直激光分别瞄准吸附于工件两端的磁性定位块,由四象限光电池接收判断。轻质粗糙导轨造成的误差由CCD器件探测并加以补偿,用激光干涉仪完成测长。     

激光调阻机多档测量误差的软件自适应校正

为了减小激光调阻机测量系统的多档测量误差对阻值修调精度的影响,提出了一种基于有源单臂电桥测量原理自适应地校正激光调阻机多档测量误差的方法.通过测量和标定高精度标准电阻的测量误差,自适应地获取校正激光调阻机多档测量误差的系列修正值,进而用系列修正值对所有待修调电阻的阻值测量误差进行校正,达到进一步减小系统测量误差的目的.实践证明,在测量硬件电路保证高稳定性、微小波动性测量的前提下,应用该方法可使测量系统的精度指标达到:低阻区(R<100Ω)为±0.5‰;中阻区为±0.2‰;高阻区(R≥1MΩ)为±2‰.     

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。     

双频激光干涉仪动态测量系统

一、引言双频激光干涉仪是以激光波长为基准的精密测试仪器。它不仅可作为长度、角度和平直度等测量基准,而且体积小、便于携带,可在计量室、车间及环境要求不高的场合使用。因而,它在机床和三座标测最机等的几何精度和定位精度的测定,仪器测量精度的标定等方面都得到广泛的应用。     

Elden公式法在双频激光干涉仪测量系统的应用

双频激光干涉仪测量系统是以激光波长为测量基准,在空气中传播的激光波长会受到空气折射率变化影响,分析了现有的激光波长补偿方法,重点对间接补偿法中的Edlen公式法进行了研究.搭建了一套双频激光干涉仪测量的实验平台,并对不同光程下实验平台的稳定性进行了测试,结果表明:实验平台的测量值能达到m量级,具有较好的稳定性.采用高精...     

测量激光高反射镜散射率的激光散射仪

本文介绍了激光散射仪的测量原理、仪器结构及测量误差分析。仪器实际测量结果:灵敏度为4×10_(-6),相对测量精度优于±10%。     

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′.     

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.