齿轮螺旋线偏差比较测量结果的不确定度评定

要提高齿轮螺旋线的测量准确性,使用螺旋线样板或标准齿轮作为标准,用上级计量部门测量的螺旋线样板或标准齿轮的数据对齿轮螺旋线测量仪的示值进行修正,再测量齿轮螺旋线,消除齿轮螺旋线测量仪的系统误差。本文将从齿轮螺旋线最基本的展成原理深入全面分析齿轮螺旋线倾斜偏差测量结果的影响量,同时进行测量不确定度评定。     

运动误差对齿轮螺旋线偏差测量的影响

考虑机构运动偏差的条件,给出了坐标法测量齿轮螺旋线偏差的测量原理和计算方法。通过比较齿轮螺旋线测量的方法,得出不同方法的优缺点。坐标法测量齿轮螺旋线偏差具有不需要特别高精度的展成机构的优点,但机构运动误差对齿轮螺旋线偏差测量有较大的影响,在自主开发的齿轮测量中心平台上,根据测量原理和误差定义,给出了齿轮测量中心螺旋线偏差的计算公式,并以圆柱斜齿轮测量数据验证运动误差对螺旋线测量精度的影响程度。     

基于运动合成与分解思想的环面蜗杆螺旋线测量方法研究

结合环面蜗杆螺旋线的方程,将运动轨迹合成与分解的思想运用到环面蜗杆螺旋线测量上面。通过构造简单运动轨迹合成螺旋线轨迹,利用简单轨迹的测量达到环面蜗杆螺旋线轨迹测量的目的。本文对测量方案的多样性和方便性进行讨论,并对测量方案的测量误差进行了理论分析,为测量方案的误差修正与补偿提供理论基础。在试验研究方面,结合环面蜗杆螺旋线测量平台对标准蜗杆进行螺旋线测量,通过测量数据进一步对测量方法进行验证和分析。     

考虑安装误差的 ZC1 蜗杆螺旋线偏差评定方法

安装误差对齿轮测量中心的测量结果影响较大。 针对其中 ZC1 蜗杆螺旋线偏差评定问题,在齿轮测量中心 ZC1 蜗杆 螺旋线测量原理基础上,分析了安装误差对蜗杆测量的影响机理,建立了安装误差修正模型,并依据螺旋线偏差定义建立了基 于安装误差修正的 ZC1 蜗杆螺旋线偏差评定方法。 在齿轮测量中心上对 ZC1 蜗杆开展了螺旋线偏差测量试验,得到初始安装 状态和安装误差条件下的螺旋线偏差评定结果,对比初始安装状态,安装误差修正前后多次测量结果之间的最大差异由 76. 2 μm 降为 4. 2 μm。 提出的 ZC1 蜗杆螺旋线偏差评定方法可有效减小齿轮测量中心测量过程中安装误差对螺旋线偏差测 量结果的影响。     

手动三坐标测量机测量丝杠副螺旋线误差

在丝杠螺旋线误差测量原理的基础上,分析用手动三坐标测量机测量丝杠副螺旋线误差存在的问题。找出了一种在三坐标测量机上测量丝杠螺旋线误差的方法及其理论依据,总结了测量中的注意事项和这种测量方法的局限性。     

投影法CCD测径系统

文中介绍以线阵CCD作为光电传感器的投影放大法线径测量系统,着重分析提高系统稳定性和测量精度的方法。系统以半导体激光器为光源,成像系统采用物方远心光路。对阴影图像进行一阶微分并求其局部重心点作为其边缘特征点。对光学系统放大倍数和成像系统像差分别进行线性、非线性标定以提高测量精度。     

改进后的齿轮测量中心Mahr891E螺旋线偏差测量系统测量不确定度评定

分析和计算了这台在数字控制系统和部分机械部件都经改进了的齿轮测量中心Mahr891E螺旋线偏差测量系统的测量精度,应用光学测量系统测量了各部分运动系统精度,经理论计算螺旋线偏差测量系统测量不确定度,可知这台改进后的齿轮测量中心Mahr891E螺旋线偏差测量系统可以完成标准Cylindrical Gears-ISO System of Accuracy和GB/T10095,1-2001中所规定的超精密齿轮螺旋线偏差测量任务。     

高精度蜗杆螺旋线智能测量

本文介绍了WLY－1高精度蜗杆螺旋线智能测量仪的工作原理，误差分析和实测结果。该仪器全部测量过程由计算机控制，自动实现分头和螺旋线误差。齿距偏差、齿距累积误差等参数的测量，以及数据采集、处理和打印输出．其精度性能指标达到同类仪器世界先进水平，可用于检测三级和三级以上精度蜗杆的螺旋线误差。     

丝杠螺旋线误差动态测量方法的研究

丝杠是工业生产中重要的传动部件,其自身精度往往对整个系统的精度起着决定作用。因此,丝杠螺旋线误差的测量有着重要实际价值。针对目前丝杠螺旋线误差检测系统的不足,对以往的测量方法进行了改近,设计了以双频激光干涉仪作为长度测量的标准,以圆光栅作为转动角度的测量的标准,数据处理上利用可编程逻辑器件(CPLD)为核心电路的计算机测量方案。在此基础上,进行了样机实验研究和试运行,运行结果证明,测量系统能够实现2级以上丝杠螺旋线误差的动态测量,具有测量效率较高,能够对环境造成的偏差进行补偿的特点。     

大型齿轮在机检测螺旋线偏差信号的采集和分析

针对直径大于2.5m的大型齿轮的螺旋线偏差开展了在机测量研究.在分析其测量原理与方法的基础上,进行检测信号的采集与分析,并通过测量试验研究分析其误差影响因素及测量过程存在的问题.     

A novel depth-from-focus-based measurement system for the reconstruction of surface morphology with depth discontinuity

Errors due to magnification variations are caused in optical systems when three-dimensional shape measurements based on depth-from-focus (DFF) are performed. These magnification variations cause focus measures to be incorrectly interpreted. In this paper, a DFF-based system which considers the magnification variations has been developed to undertake accurate measurements of surface morphology with depth discontinuity. The image magnification can be represented by magnification factors, which are computed using the ratio of diagonal image lengths of a rectangular calibration block, according to optical system movements. The image calibration is performed using the magnification factors. The calibration makes the image size of the object features identical, in spite of magnification variations resulting from optical system movements. Therefore, the application of accurate and reliable focus measures is made in the calibrated images. The performance of our presented system has been verified through experiments with actual objects with depth discontinuity.     

四极质谱检测中复合放大器的低噪声高带宽设计

四极质谱峰信号是10-11A到10-6A级的微弱电流,并且快速变化,所以在大动态范围内实现低噪声和高带宽是设计关键。设计一种开环增益(ac)可调整的同相输入复合跨阻抗放大器,分析ac对信号和噪声的作用。在较低放大倍率时,改变ac后同相输入复合放大器会降低自身产生的噪声,实现低噪声;在较高放大倍率时,改变ac后同相输入复合放大器能扩展被极高阻值的反馈电阻和寄生电容降低的信号带宽。实验结果表明：与反相输入复合放大器相比,同相输入复合放大器在106-107V/A放大时能降低5-30%噪声,在108V/A放大时扩展带宽1.8倍并提高10-15%质谱峰强度,提高了质谱峰的信噪比。     

Collection deficiencies of scanning electron microscopy signal contrasts measured and corrected by differential hysteresis image processing

Limitations of scanning electron microscopy (SEM) image resolution and quality were measured in digital image data and their effect on image contrasts was analyzed and corrected by differential hysteresis (DH) processing. DH processing is a mathematical procedure that utilizes hysteresis properties of intensity variations in the image for a segmentation of differential contrast patterns. These patterns display contrast properties of the data as coherent full-frame images. The contrast segmentation is revertible so that the original image can be restored from the sum of the sequentially extracted DH contrast patterns. DH imaging enhances weak contrast components so that they are more easily recognizable and displays SEM image data free of signal collection efficiency contrasts. Example image data include environmental SEM (ESEM) and SEM images of low and mediumhigh magnifications where collection deficiencies included charging of the specimen surface, obstructions from specimen topography, and uneven signal collection properties of the detector. ESEM low-vacuum image data, which appear to be of high quality, contained local areas of reduced contrasts due to residual surface charging. In such areas, signal contrasts were reduced up to 80%, which suppressed most of the weak short-range contrasts. In low-magnification SEM images, up to 93% of the local high precision contrast was lost from the various adverse effects which diminished the pixel-related contrast resolution of the microscope and resulted in images with low detail. Also, at medium magnification, surface charging effects dramatically reduced the image quality because contrasts resulting from local electron beam/specimen interactions were reduced by as much as 71%. DH imaging restored the local contrast losses by elimination of the collected distorted fraction of signal contrasts and reconstitution of the collected maintained fraction. Restored DH images are of superior quality and enhance the imaging capability of the conventional SEM. DH contrast segmentation provides an improved basis for the measurement of various signal contrast components and detector performances. The DH analysis will ultimately facilitate a precise deduction of specimen properties from extracted contrast patterns.     

A focusing algorithm for high magnification cell imaging

An algorithm to produce a uniformly focused image in digital acquisition of high magnification light microscopy images is presented. In very high magnification microscopic imaging the specimen surface cannot be considered ideally flat so that capturing a single image frame is usually not sufficient to capture an image that is focused everywhere. An image formation model for light microscopic images is presented, and based on this model an algorithm to construct a uniformly focused image is presented. The algorithm requires that multiple frames of the image at different focal planes be processed to combine their information to obtain an estimated of the desired image which is more completely focused than any of the individual frames. Experimental results show that the proposed algorithm is very effective in approximating the desired image in high magnification microscopic imaging and highly robust comparing to the gradient method.     

A new light microscopic method for the synchronous bidirectional illumination and viewing of living cells in different contrast modes, and/or at different focal levels or magnifications.

A new method of light microscopy for the analysis of the behaviour of living cells in vitro exploits two objects for simultaneous image formation, each serving the other as a condenser. Simultaneous viewing from opposite sides allows the specimen to be examined at: (a) two different magnifications, permitting the locomotion of whole cell (groups) to be studied at a low magnification and details of interaction of colliding surfaces at a high magnification; (b) two different focal levels, permitting, for example, details near the substrate surface to be recorded at the same time as information concerning the behaviour of the free, dorsal surface; and (c) two different contrast modes, such as negative and positive phase contrast, and dark and bright field illuminations. These possibilities can be combined, for example, to contrast a high magnification view in negative phase contrast at one focal level with a low magnification image in ordinary brightfield at another focal level in the same living cells.     

微缩投影系统的垂轴放大率测量

考虑有限距光学系统的成像质量与系统垂轴放大率相关,本文提出了基于系统波像差检测的垂轴放大率测量方案。以给定的光学系统中像平面位置与物平面位置满足高斯公式和牛顿公式的原理为出发点,通过系统波像差中离焦量的变化监控物点移动微小量后像点的移动距离。然后,对牛顿公式或高斯公式微分导出轴向放大率,最终求出系统垂轴放大率。建立了垂轴放大率测量模型,给出物点的微小位移量和初始离焦量的选取标准,并系统地分析了光学元件形位公差和像点定位精度对垂轴放大率测量结果的影响。搭建了基于点衍射干涉仪的微缩投影系统波像差检测平台,测量了系统的垂轴放大率。实验显示,系统垂轴放大率的测量值与理论值的偏差优于0.24%,验证了提出的垂轴放大率测量方法的可行性和理论分析的准确性。     

铁谱磨粒图像多焦点融合算法研究

铁谱分析技术是一种常用的磨损监测技术。受限于高倍物镜下的景深限制,一张铁谱大磨粒图像往往只有局部聚焦清晰的特征。为了能够解决在高倍物镜下铁谱大磨粒图像的自动化清晰采集以及高质量图像融合问题,设计并构建一套自动化扫描显微系统,该系统可进行多焦点铁谱图像的自动扫描采集;同时,提出一种基于相位一致性的铁谱磨粒图像多焦点融合算法,对自动扫描的多焦点图像进行融合,得到清晰的磨粒图像。实验结果表明,设计的自动化扫描显微系统能快速完成多焦点铁谱图像的自动化采集流程,提出的图像融合算法相较于传统的小波图像融合算法具有更高的图像评价质量,并能获得更加清晰的图像边缘信息。     

Image sharpness measurement in scanning electron microscopy—part II

A method for qualitative and quantitative analysis of scanning electron microscope (SEM) images forthe determination of sharpness is presented in this paper. Described is a procedure for qualitative analysis based on a software program called SEM Monitor that can be applied to research or industrial SEMs for day-to-day performance monitoring. The idea is based on the fact that, as the electron beam scans the sample, the low-frequency changes in the video signal show information about the larger features and the high-frequency changes give data on finer details. The image contains information about the primary electron beam and about all the parts contributing to the signal formation in the SEM. If everything else is kept unchanged, with a suitable sample, the geometric parameters of the primary electron beam can be mathematically determined. An image of a sample, which has fine details at a given magnification, is sharper if there are more high frequency changes in it. In the SEM, a better focused electron beam yields a sharper image, and this sharpness can be measured. The method described is based on calculations in the frequency domain and can also be used to check and optimize two basic parameters of the primary electron beam, the focus, and the astigmatism.     

A specimen scanner for stereology with the electron microscope

Stereological methods which involve the use of test grid systems with electron micrographs suffer from a basic limitation that the magnification used has to be a compromise between high magnification for good visibility of image detail and low magnification for good sampling. The electron microscope scanning stage described avoids this difficulty since high magnification imposes no limitation on the sampling of the specimen and in practice can be used for situations where test grid methods become impractical.     

Application of Monte Carlo modelling in the measurement of photomask linewidths at the national physical laboratory

A scanning electron microscope (SEM) fitted with a helium-neon laser interferometer is used to measure the widths of features on photomasks. In this way the magnification of the SEM can be known very precisely. Algorithms which use the backscattered electron (BSE) signal, yielding good measurement repeatability, have been developed, but in order to be able to relate measurements made on the image to the physical dimensions of the artefact, it has been necessary to model the image formation process. The modelled predicted offsets to be applied to the experimental measurements are governed largely by the angle of the sloping sides of the chromium edges of photomask lines; knowing this angle, it is possible to use a simple geometric relation to calculate what offset should be applied.