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自准直仪与反光面准直时的注意事项 总被引:3,自引:0,他引:3
自准直仪与反光面准直时,防止准直误差增大的注意事项有:测量装置旋转轴线与自准直仪测量线的平行度、与反光面平行度的变化量; 反光面的平面度、自准直仪出射光束平行度、反光面与自准直仪中心对准的变化量;采用五棱镜转向90°准直时五棱镜顶线和测量面的垂直度和采用三棱镜作反光镜时的棱线水平度等。本文阐述了这些因素形成准直误差的机理, 估算和解决方法。 相似文献
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利用光学自准直仪和五棱镜组合测量直角尺的垂直度,方法简便易行。现以哈量1401型平面度检查仪为例说明。如图所示,将一直径为φ50,长400mm的圆柱1(其直线度要求<1μm。)加工出下上两平面。把带座平面反射镜2固定在上平面上。测量时应保证圆柱母线大体与被检直角尺4中心相切。测量时,先将直角尺平放在零级平板上并固定。带平面反射镜的长圆柱紧靠直角尺底边,自准直仪6对准平面反射镜。调整自准直仪,使反射像基本在自准直仪视场中央,读出第一个测量值x_1。然后将带反射镜的长圆柱移到长边并靠紧(如图1虚线所示),在两柱交接处放置五棱镜3。这时反射像很可能不在 相似文献
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由于弹性多齿分度盘广泛应用于测角中,角度测量的精度越来越高。因此,对影响精度的各种因素都必须加以考虑,如光管轴线的调整,多面棱体的平面度误差及其工作面与下底基面的垂直度误差等,都会给测量带来误差。图为自准直光管的视场图,yy轴是安放多面棱体的转台轴向;十字线是镜面反射回来自准直光管指标线的像;ss是测反射象位移用的分划板;xx是转动多面棱体时十字线象移动的方向。如图所示,当自准直光管偏斜时,分划板十字线竖线与yy轴倾斜为Φ角, 相似文献
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精密回转工作台的倾斜角度对角度测量、工件形貌测量的结果产生系统性误差。为消除该影响,提出一种基于平面矢量分析的转台调平方法。以三点支承转台结构为研究对象,通过对转台工作面倾斜矢量的测量与分析,建立平台的调平方程;通过自准直仪测量倾斜矢量可以计算得到支承柱的高度调整量,从而实现转台调平。实验结果表明:现有实验条件下,转台工作面倾斜角的测量标准差为0.6″,经过2次调平可使转台工作面倾斜角小于2.0″。该调平方法具有数学原理简单、调平精度高等特点,可为转台自动调平的实现提供新的途径和方法。 相似文献
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用自准直仪测量垂直度,具有方法简便易行、可直接在生产现场使用且测量准确度较高等特点。现将我厂在生产中的两应用实例介绍如下。一、端面对内孔轴线的垂直度测量我厂生产的某零件,其端面平面度、端面对内孔轴线的垂直度要求都很高。生产中,若采用研磨、送检、再研磨的方式,费时费力,效率低。为此,我们设计了一套测量装置(见图1),在生产现场实现了垂直度的高准确度、快速测量。其中,镶嵌在工装上的5个钢球(排列见图2)使工件能准确定位。测量时转动工件,通过自准直仪中读数变化即可求出所测的垂直度。二、四方块类零件各相邻面间垂直度的测… 相似文献
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工作平台的倾斜会导致自准直仪在配合转台进行角度测量时产生测角误差,研究该倾斜引起的误差规律不仅对提高测角精度具有重要意义,还对实现测角仪器的标定具有参考价值。论文首先基于三个状态参数(平面倾斜角θp、反射面方位角θx、反射面垂直度?),通过齐次坐标变换推导建立转台配合自准直测角时由平台倾斜导致的误差数学模型;接着以模型中的θx为自变量,在不同量级的θp、?的取值下仿真得到多组误差曲线,对比分析并总结该误差的分布规律;最后,基于该误差的特性提出一种自准直测角标定方法,分析表明,取反射面方位角θx=90°时,该方法可实现每步大小为θp·?的角度改变量,是标定自准直仪的一种可行途径。 相似文献
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分析了经纬仪横轴与竖轴垂直度误差的产生原因及该误差对水平方向观测值的影响,给出了该误差的检定方法,对高低点法和高平点法检定精度进行了分析,并以实验进行了验证。 相似文献
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Jack A. Stone Mohamed Amer Bryon Faust Jay Zimmerman 《Journal of research of the National Institute of Standards and Technology》2004,109(3):319-333
We have studied a number of effects that can give rise to errors in small-angle measurement systems when they are used to calibrate artifacts such as optical polygons. Of these sources of uncertainty, the most difficult to quantify are errors associated with the measurement of imperfect, non-flat faces of the artifact, causing the instrument to misinterpret the average orientation of the surface. In an attempt to shed some light on these errors, we have compared autocollimator measurements to angle measurements made with a Fizeau phase-shifting interferometer. These two instruments have very different operating principles and implement different definitions of the orientation of a surface, but (surprisingly) we have not yet seen any clear differences between results obtained with the autocollimator and with the interferometer. The interferometer is in some respects an attractive alternative to an autocollimator for small-angle measurement; it implements an unambiguous and robust definition of surface orientation in terms of the tilt of a best-fit plane, and it is easier to quantify likely errors of the interferometer measurements than to evaluate autocollimator uncertainty. 相似文献
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从测量值计算非球面参数 总被引:1,自引:0,他引:1
为解决按测量值计算非球面光学系统成像质量的问题,提出了一种从三维坐标测量值提取标准非球面方程的参数的方法.首先在两个相互垂直的近似的中心剖面附近取值,并分别投影到这两个平面上;然后拟合曲线;再用这两条曲线在各自的平面内截取一组平行直线成一组线段,改变直线的斜率,使各线段中点共线,确定非球面的对称轴和顶点坐标;最后,平移、旋转坐标系后,将三维坐标降维,用多项式拟合成二维曲线,同时将标准形式方程中的无理项展为泰勒级数,对比二者的系数并推广,得到任意偶数阶标准非球面方程的参数.大量随机取值计算的统计结果表明,算法的误差是测量误差的1/2. 相似文献
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A new method to calibrate the autocollimator with small angle measurement range has been developed. This method used a system based on rotary encoder for angle measurements with self-calibration function (SelfA47). The SelfA47 has 18,000 graduation lines with angle interval of 0.02°, corresponds to 72 arcsec. Thereby this system cannot be used to calibrate the autocollimator with measurement range <72 arcsec. On the other hand, SelfA47 can be used to calibrate an electronic level. The deviation of electronic level shaped linear gradient. Therefore a small nominal gradient of electronic level can be approximated by interpolation. Since the gradient of a curve corresponds to the angle quantities, it is feasible to calibrate the autocollimator with nominal angle <72 arcsec using SelfA47 and an electronic level. In this proposed method, SelfA47 is placed horizontally on the same plane with electronic level and mirror reflector position. The electronic level value that have been corrected by SelfA47 is used as a reference. This reference value was converted to the angle, thus the angle deviation of autocollimator can be determined. The prominent uncertainty of angle measurement using this new technique derived from the uncertainty of electronic level and rotary encoder. Using this method, the expanded uncertainty of 0.36 arcsec is obtained from calibration of autocollimator with measuring range of ±20 arcsec and it is consistent statistically with the manufacturer calibration result shown by E n value is <1. In conclusion, this approach method can be applied to calibrate the autocollimator with a resolution smaller than SelfA47 as standard, but it is not recommended for the calibration of highly accurate autocollimator. 相似文献
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《IEEE transactions on instrumentation and measurement》1964,13(4):265-272
Impedances of devices with coaxial inlets, having small reflection coefficients relative to a given characteristic resistance, can be determined accurately (± 0.1 per cent) by comparison with the nominally calculable characteristic impedance of a quarter-wavelength, air-spaced coaxial line in which the inner conductor is supported by the inner conductors of the apparatus connected at each end. In carrying out such comparisons, errors may be introduced by the presence of small series impedances at the connections between the rigid coaxial lines. Such connections cannot be eliminated because they must be made and broken during the process of making comparisons. Errors may also arise from the distributed resistance and the "internal" reactance of the line conductors, as well as from departure of the lines from uniformity in diameter. This paper describes experimental techniques for measuring these residuals and discusses their effects. The design requirements of suitable air-spaced coaxial lines as standards are stated, together with a brief mention of techniques for making comparisons with the standards. 相似文献
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提出了一种实用的大型工件平面度、平行度、垂直度误差的计算与评定方法。这种方法适用于各种不规则、不连续的测量表面。评定程序采用最小二乘和最小条件法,搜素速度快,评定结果精度高。 相似文献
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数显式自准直仪使用时,气流等环境条件的影响以及仪器本身发热等原因都会引起示值的漂移和跳动,使测量误差增大、测量结果不能回零。采用增加一块固定反光镜作为参考镜,它与工作反光镜以自准直仪进行差动,组成自校准系统,可以有效地进行消减。仅用工作反光镜时2h内的漂移量为0.03″,经自校准系统后为0.01″;样本标准偏差为0.091 1″,经自校准后为0.057 4″。差动式反光镜自校准系统可以显著减小CCD自准直仪的示值漂移,对减小示值跳动也具有一定作用。且无论是对环境条件还是仪器本身原因引起的漂移和跳动都是有效的。 相似文献