基于反向共轴的大口径平面光学元件面形测量

提出了一种基于反向共轴的大口径平面光学元件面形测量方法。将双位移传感器反向共轴线扫描测量模式和多角度旋转三面互检技术结合,借助直线长导轨有效扩大平面光学元件测量口径,同时测量过程中不需要使用标准平晶,避免引入标准平晶参考面不确定度分量,测量结果直接溯源到激光波长基准。利用该测量方法对3块400mm口径光学平晶进行面形测量,验证了该测量方法的可行性。     

Calibration of a 300-mm-aperture phase-shifting Fizeau interferometer

A 300-mm-aperture digital phase-shifting Fizeau interferometer has been developed in-house for precision metrology of optical components fabricated by the optical workshop at Telecommunications and Industrial Physics, Commonwealth Scientific and Industrial Research Organization. We describe the procedures used in the calibration of the instrument. A reference data file representing the deviations from flatness of the reference surface is generated, measurement uncertainty estimated, and aberrations in the instrument assessed. Measurements on 250-mm-diameter uncoated optical surfaces have consistently shown short-term repeatability of 0.3-nm rms from measurement to measurement and allowed for absolute characterization of these surfaces to within a few nanometers.     

对角线法评定平面度误差数学模型的探讨

平面度是几何量测量中的一个重要参数。测量得到的平面是利用理想平面作为基准，使其它计量器具有相应的参照平面，从而对其平面度进行评定。本文根据对角线评定方法，对平面度测量的数学模型及不确定度的评定进行了探讨。     

基于相移干涉仪的平面度测量软件设计

以相移干涉法测出的点阵波面数据为基础,设计了计量用平面度测试软件Flat Ex,包括标准平晶的绝对检验、研磨面平尺的斜入射测量和子孔径拼接及三个功能算法模块。通过与等倾干涉仪检定过程的比较,从理论上说明从密集点阵数据中提取稀疏点数据的合理方法,以符合规程的要求或约定俗成的做法。程序已经用于处理Matro Pro和Phase One等多种相移干涉仪数据,提取出符合要求的平面度结果。在相移干涉仪与等倾干涉仪检定结果进行比对实验中,表现出良好的一致性。     

Absolute testing of optical flats at points on a square grid: error propagation

The absolute testing of optical flats through the use of the rotation-shift method is discussed. Absolute deviations of three flats are determined by the evaluation of at least four interference patterns of pairs of these flats. In the rotation-shift method the absolute deviations are calculated at the points of a square grid. The propagation of error in measurements of the interference patterns to the magnitude of the error of the overall result is calculated with respect to special combinations of pairs of the flats. Proposals are made to minimize the error propagation. The mean-square value of the error-propagation factors is in the range of 0.75. Square grids of up to 151 points × 151 points are used.     

The Difference Between GUM and ISO/TC 15530-3 Method to Evaluate the Measurement Uncertainty of Flatness by a CMM

Uncertainty estimation in coordinate measuring machine (CMM) measurements is one of the highest priority tasks in modern industrial world due to its importance in the manufacturing metrology, especially if we take into account the fact that workpieces, according to a new generation of geometrical product specifications, can be accepted/rejected only on the basis of the total measurement results. Evaluation of measurement uncertainty of a CMM is a complex task, especially in the verification of errors of forms. Among several standard methods that can be used to estimate measurement uncertainty, we performed a comparison between two of these for the case of flatness measurement. Optical flat was used in order to exclude a number of essential factors in the case study. The results showed that the expanded measurement uncertainty assessed by GUM is greater than the value of the expanded measurement uncertainty obtained using the ISO 15530 method. However, both methodologies have shown that the maximum permissible error of a CMM has the greatest impact on uncertainty and also, that the total result evaluated by both approaches is close to the maximum permissible error of a CMM.     

Measurement uncertainty estimation in real experimental conditions of ultrasonic interferometer manometer established at NPL, India

The National Physical Laboratory, India, has established an ultrasonic interferometer manometer (UIM) as a primary standard in the barometric pressure region. This paper reports the results of the measurement uncertainty of the UIM evaluated under experimental conditions at each pressure point through a software developed and integrated with the existing operating software program. Through the operating software program, an initial estimate of column length using time-of-flight and four predefined ultrasonic frequencies with the help of an exact fractions algorithm is made, but the final pressure is calculated from the measurements made at multiple frequencies. At a particular pressure point, 44 measurements are made at different frequencies, covering two full circles (fringes). The mean of these 44 measurements is taken as the measured pressure to minimize the uncertainty contribution due to systematic phase error. In the present uncertainty evaluation, the standard deviation of this mean is taken into account in estimating the measurement uncertainty in real experimental conditions. The uncertainty thus estimated has been compared with that uncertainty, evaluated theoretically, as per ISO Guide to the Expression of Uncertainty in Measurements. This experimental determination of measurement uncertainty has helped us in making further improvements in the measurement accuracy of the UIM, especially at low-pressure measurements.     

CMM形状测量任务的不确定度分析与评定

研究了坐标测量机(CMM)形状测量任务的不确定度评定问题,实现了CMM形状测量的不确定度快速、可靠地评定。给出了测量不确定度评定与表示指南(GUM)和蒙特卡洛随机抽样两种不确定度合成方法,平面度测量实验验证了不确定度评定方法的可行性,实验结果表明:GUM确定的不确定度精度意义不可靠,扩展不确定度相对于实际情况扩大了11.1%; 解决CMM形状测量任务的不确定度评定问题,具有较强的典型性和代表性,可有效地应用于解决其他精密仪器的不确定度评定问题。     

A Railway Measurement System to Evaluate the Wheel–Rail Interaction Quality

This paper deals with the problem of measuring the wheel-rail interaction quality in real time using a suitably designed and realized railway measurement system. More specifically, the measured parameter is the equivalent conicity, as defined in the international union of railways UIC 518 Standard, and the measurement system is based on suitable processing of geometric data that is acquired by a contactless optical unit. The measurement system has been verified according to the test procedures described in the UIC 519 Standard. This paper shows how it is possible to obtain, in real time and with comparatively simple algorithms, measurements that are perfectly compliant with the UIC 519 Standard, with regard to the required measurement uncertainty as well.     

高精度平面度测量方法的研究

本以中等尺寸０００级平板为研究对象,采用双频激光测量系统的直线度测量部件进行平面度测量,分析计算了这一测量方法的测量不确定度,并进行了实际测试。     

带旋转的三面互检法

按传统三面互检法评价平面度偏差,结果只能由评价平晶在两条相互垂直的直径线上的测量数值得到,其评价方法与平晶的真实面形偏差存在差异.本文介绍的基于光电探测技术、激光干涉技术、图像处理技术的带旋转三面互检法可以解出平面上N条直径线上的点的面形偏差,可以提高测量准确度.     

挡水闸门平面度测量

介绍一种利用经纬仪和游标量具测量福建水口电站船闸挡水闸门平面度的方法;按最小包容区域法评定被测闸门平面度误差值;对测量不确定度进行了分析和评定.     

Measurement Uncertainty of Dew-Point Temperature in a Two-Pressure Humidity Generator

This article describes the measurement uncertainty evaluation of the dew-point temperature when using a two-pressure humidity generator as a reference standard. The estimation of the dew-point temperature involves the solution of a non-linear equation for which iterative solution techniques, such as the Newton?CRaphson method, are required. Previous studies have already been carried out using the GUM method and the Monte Carlo method but have not discussed the impact of the approximate numerical method used to provide the temperature estimation. One of the aims of this article is to take this approximation into account. Following the guidelines presented in the GUM Supplement 1, two alternative approaches can be developed: the forward measurement uncertainty propagation by the Monte Carlo method when using the Newton?CRaphson numerical procedure; and the inverse measurement uncertainty propagation by Bayesian inference, based on prior available information regarding the usual dispersion of values obtained by the calibration process. The measurement uncertainties obtained using these two methods can be compared with previous results. Other relevant issues concerning this research are the broad application to measurements that require hygrometric conditions obtained from two-pressure humidity generators and, also, the ability to provide a solution that can be applied to similar iterative models. The research also studied the factors influencing both the use of the Monte Carlo method (such as the seed value and the convergence parameter) and the inverse uncertainty propagation using Bayesian inference (such as the pre-assigned tolerance, prior estimate, and standard deviation) in terms of their accuracy and adequacy.     

Evaluation of Measurement Uncertainty Based on the Propagation of Distributions Using Monte Carlo Simulation

The uncertainty associated with a value of some quantity is widely recognized throughout scientific disciplines as a quantitative measure of the reliability of that value. In addition, measurement uncertainty is increasingly seen as essential in quality assurance for industry. The Guide to the Expression of Uncertainty in Measurement (GUM) provides internationally agreed recommendations for the evaluation of uncertainties. This paper outlines the current situation of uncertainty evaluation in the context of international norms and arrangements. It describes the basic ideas and concepts that underlie the GUM and serves as a brief tutorial on methods for evaluating measurement uncertainty in a manner consistent with the GUM. It recommends an approach to evaluating measurement uncertainty based on the propagation of distributions using Monte Carlo simulation. An example is presented to illustrate Monte Carlo simulation.     

光纤综合特性测试仪测量不确定度评定

根据计量工作中测量不确定度评定的实践经验,对光纤综合特性测试仪在计量时的测量不确定度进行了分析、评定。     

平晶表面形状加压分析判断法的原理与应用探讨

平晶表面形状的判断对于平晶平面度的计算非常重要，错误的判断将会直接导致计算错误。该文通过对加压分析判断法原理的介绍，讨论在实际检定工作中的注意事项。灵活掌握该方法不仅对于平晶检定工作，而且在使用平晶测量量具或工件表面平面度时都非常重要。     

平面光学元件平面度动态干涉拼接测量

开展了基于动态干涉仪的平面光学元件平面度干涉拼接测量,并研究了影响测量和拼接的主要误差。用二级减振的方法来抑制环境中振动的影响;根据允许的变化条纹数来控制二维移动平台导轨精度。建立了以ZYGO公司的DynaFiz干涉仪为子口径采集仪器的干涉拼接系统,开展了单口径平面度测量及拼接实验,完成了200mm×300mm 平面光学元件的平面度测试,并与大口径干涉仪所测试的全口径测量数据进行比对,拼接结果的10次实验均方差为0.001λ(λ=632.8nm)。     

（2／3）d范围内平晶平面度测量方法分析

在JJG28-2000平晶检定规程中,对平晶有效直径d范围内的平面度和（2／3）d范围内的平面度均有规定的要求。但该规程附录D中的计算公式和图示并不是平晶有效直径d范围内的平面度测量方法,且没有给出（2／3）d范围内的平面度测量方法,该文将对此问题进行分析,最后给出了符合现行规程要求的新测量方法,补充了计算公式。     

平面度计量——点线面之间的量值传递与控制

研究了平面度计量中的线和面两种传递路径。针对通过等厚干涉仪的面传递中不能维持平面度指标的原始定义,必须采用光圈(N、ΔN)等指标来描述的问题,在讨论测量点的绝对检验方法的基础上,提出了解决直线和面域上不同的平面度指标体系的统一的方法。分析了《JJG 28-2000 平晶》中以点控线和以线控面过程中的假设和附加要求对于传递精度的影响问题,提出了基于相移干涉仪高分辨率和快速测量的优势,采用圆平晶以最大变化正交截面替代国标中随机的“任意”正交截面的方法,从而保证对平晶平面度计量的严谨性要求。     

面向非稳态传热的热像仪相对测温性能评估

提出了一种热像仪相对测温的性能评价方法。将薄片热电偶的热节点固定在温度场均匀的加热单元表面,作为标准辐射温度发生单元,被待评价的热像仪观测和测温,对比热像仪观测的热电偶热节点表面温度场数据和热电偶自身测得的温度数据的相似度,对热像仪相对测温性能进行评价。基于国内外4个品牌的7款不同规格热像仪进行测试,结果表明热像仪的相对测温误差和绝对测温误差相差较大,相对测温误差通常介于噪声等效温差和绝对测温误差之间,同时发现6号热像仪性能较差,温漂严重,通过装置中的A、B两靶标同时测试热像仪性能,评价结果的标准差均在8%以内,这表明该方法具有较高的可靠性,对热像仪相对测温性能评价研究有一定的参考意义。