自准直测量系统中离焦误差分析及修正

在自准直角度测量系统中,当光电接收装置即四象限探测器偏离透镜焦平面时,会在测量系统中引入离焦误差。为提升自准直测量系统的精度,该文利用实验室已有的自准直角度测量系统,将反射镜角度对处于离焦状态的测量系统产生的影响进行分析,利用雷尼绍激光干涉测量系统测得角度值作为标准量,与测量实验系统测得角度量进行对比,根据测量结果求出离焦距离。从实验结果可以看出,将离焦距离求出并对四象限探测器与透镜间间距进行调整后,自准直角度测量曲线重合,证明将离焦误差有效消除。     

二维自跟踪视觉准直测量系统

为了提高自准直仪的测量精度和降低人眼瞄准的劳动强度和主观误差,提出一种基于机器视觉的二维自跟踪视觉准直测量系统。该系统由光学准直仪、CCD和图像采集卡等组成。以面阵CCD代替人眼对自准直仪的十字分划板图像进行瞄准;采用图像不变矩自动搜索算法和hough变换、亚像素细分等方法实现对小角度的自动精确测量。实验结果表明,该系统测量范围达到±15',最小分辨力优于0.1″,与MJS双频激光测角系统比对误差在0.6″以内,测量精度高于MJS,而且操作方便,易于推广。     

21位双通道旋转变压器解码及测试数据分析

设计了一种基于CPLD的21位分辨率双通道旋转变压器的解码及精度测量方案.通过CPLD对AD2S82A解码输出的两路并行16位数据进行读取、纠错、编码、输出,最后输出21位角度信号,这样整个测角系统就成为了主系统的一个外设.实验中搭建测试平台,用自准直仪和多面棱镜对该测角系统精度进行测量.结果表明,测角误差均方根值达到20″,经系统误差修正后整个系统测角误差均方根值达到9.46″.最后本文对测角系统的系统误差产生原因进行了分析.     

CCD激光自准直旋转靶标轴系跳动测量系统

在检测光电测量设备的跟踪和测量精度时,动态旋转靶标能够给出空间角度的真值,而靶标轴系的跳动是影响靶标测量精度的重要因素.本文提出用 CCD 激光自准直非接触测量系统测量动态靶标轴系跳动的新方法.用面阵 CCD 采集靶标轴系跳动的视频信号,计算机对视频信号进行处理得到脱靶量数据,由此即可算出靶标轴系跳动量.实验结果表明:当靶标旋转轴以10°/s 速度旋转时,方位最大跳动量为4.80″,高低最大跳动量为3.98″,靶标轴系的旋转精度能够满足要求.     

自准直经纬仪测角系统及不确定度分析

针对结构和安装条件限制下无法直接测量安装反射镜垂直角的问题,设计了利用光电自准直经纬仪通过中间反射镜测量安装反射镜垂直角的测量系统.分析了该角度测量方法的原理,给出了测量系统的空间解算模型,利用该数学模型可修正中间反射镜的安装角度所引入的误差.在此基础上通过实验,验证了测量系统的有效性.对测量系统各不确定度分量进行了分析,得扩展不确定度为5.90″,满足了设计要求.     

精密测角仪的误差溯源及其补偿方法研究

为了简化精密测角仪的误差分析及数据处理过程,根据精密测角仪的结构组成及测量原理,对精密测角仪的误差进行溯源,并分析了各种误差源对测量精度的影响;根据精密测角仪的角度测量机理提出了一种基于被测面自准直像位置的误差补偿方法;采用精密测角仪进行被测面自准直像在不同位置时的角度测量实验,根据测量实验数据给出了误差补偿线性方程.实验结果表明:应用此误差补偿方法可有效缩减前期测量准备调整过程,使精密测角仪的应用更加便捷,简化了精密测角仪的误差分析及数据处理过程,为实现全自动精密测量提供基础.     

基于莫尔条纹的自准直测角技术

针对方位瞄准过程中的强光干扰问题,在结合光电自准直测角和光栅测长原理的基础上,提出了基于莫尔条纹的自准直测角方法.分析了基于莫尔条纹自准直测角原理,即利用自准光栅像和透射光栅重叠产生莫尔条纹,将角量变化转变为线量变化进行测量.根据该原理设计了光学系统,建立了基于莫尔条纹自准直测角的数学模型,给出了理论计算公式,并进行了测量精度分析.理论计算结果显示,在±15′的视场范围内,系统精度达到1″,优于采用狭缝时光电自准直测量的精度.     

室内GPS发射器角度校准装置的研制

室内GPS利用测量的水平角和垂直角来定位,其测角误差直接影响到系统的综合测量精度,根据室内GPS的测量原理及室内GPS角度校准的技术要求,结合精密转台、同轴调整装置和竖轴激光导轨,研制了室内GPS发射器角度校准装置,并对其测角精度进行分析计算和实验验证.实验结果表明,装置的水平角测量不确定度为1.5″,俯仰角测量不确定度为0.9″,并能够同时实现室内GPS的俯仰角及水平角的校准.     

基于平面矢量分析的转台调平方法研究

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。     

一种小角度误差快速检测方法及不确定度分析

针对传统角度误差检测设备构成复杂、使用繁琐、环境要求严苛的问题,设计了一种利用自准直经纬仪快速测量转台转角误差的检测系统。首先研究了三维空间反射模型并详细推导了模型的准确表达式;然后基于此给出了在特定条件下工程近似结果;最后结合实验完成了对检测系统的不确定度评定。扩展不确定度为8.9″,此结果验证了检测系统的有效性。     

Design and analysis of an optoelectronic inclinometer for simultaneous measurement of inclinations along two orthogonal directions

Conventional inclination measurement systems such as precision vials and capacitance measuring systems can measure inclination in only one direction at a time. We present what is believed to be a new optoelectronic system that can measure inclination angles along two orthogonal directions simultaneously by using a simple pendulum, two mirrors, a 2D position-sensing detector (PSD), and a laser diode. The light ray from the laser is projected onto a mirror that is fixed to a pendulum whose relative angle modifies in response to inclination changes of the inclinometer's housing. The light ray reflected by the mirror is sensed by the PSD, after which the signal can be interpreted by a PSD signal processor, recorded, or output to a computer. This study uses skew-ray tracing methodology to obtain implicit nonlinear system equations to model the relations of the relative inclination angles of the various components, PSD position, and world frame. A first-order Taylor series expansion is used to obtain a linear form of the system equations. To validate the proposed methodology, an actual prototype system is built and experimental results show that the performance of this system is excellent.     

坐标测量机激光非接触式测头的研制

本文介绍适用子精密大型测试仪器──坐标测量机的激光非接触式测头的研制。该测头采用ＰＳＤ作为敏感元件并采用单片机技术完成对测量数据的处理。     

Comparison of Particle Size Distributions Measured Using Different Techniques

In this article, particle size distributions (PSDs) measured by different techniques, including image analysis (IA), laser diffraction (LD), ultrasonic attenuation spectroscopy (UAS), and focused-beam reflectance measurement (FBRM), are compared for spherical glass beads and nonspherical silica flakes. It is shown that particle shape strongly affects the results obtained by different techniques. For spheres, the PSDs obtained by IA, LD, and UAS agree well. There is no consistent result among different particle measurement techniques for nonspherical particles. The conversion between PSDs obtained by IA, LD, and UAS has been based on particle shape factors. Caution must be exercised when a measured chord length distribution (CLD) is used to indicate the PSD during a process because the CLD result obtained by FBRM is complex, depending not only on the PSD, but also on particle optical properties and shape.     

Role of multiple scattering in cross-correlated light scattering with a single laser beam

Previous systems for measuring cross-correlated light scattering by small particles suspended in a liquid with multiple-scattering suppression have illuminated the particles with two laser beams. It is shown that multiple-scattering suppression should also occur in cross correlation for a system that employs a single laser beam and two closely spaced detectors with wide fields of view. The single-scattering, double-scattering, and single-double-scattering cross-term contributions to the intensity cross-correlation function are calculated. It is found that the two cross terms, when added together, are unimportant for both autocorrelation and cross correlation. The amplitude of the double-scattering term can be greatly diminished by judicious detector spacing because the spatial coherence area in the detector plane for double scattering is much smaller than that for single scattering.     

Comparison of Particle Size Distributions Measured Using Different Techniques

ABSTRACT

In this article, particle size distributions (PSDs) measured by different techniques, including image analysis (IA), laser diffraction (LD), ultrasonic attenuation spectroscopy (UAS), and focused-beam reflectance measurement (FBRM), are compared for spherical glass beads and nonspherical silica flakes. It is shown that particle shape strongly affects the results obtained by different techniques. For spheres, the PSDs obtained by IA, LD, and UAS agree well. There is no consistent result among different particle measurement techniques for nonspherical particles. The conversion between PSDs obtained by IA, LD, and UAS has been based on particle shape factors. Caution must be exercised when a measured chord length distribution (CLD) is used to indicate the PSD during a process because the CLD result obtained by FBRM is complex, depending not only on the PSD, but also on particle optical properties and shape.     

非接触大位移动态测量系统设计及实现

提出一种结构轻巧,驱动及处理电路简单,性能良好的非接触大位移动态测量方案．设计以PSD光电位置敏感器件为核心,利用半导体激光器、透镜成像装置组成的测试系统,突破了由于PSD尺寸因素而影响其测量范围的限制;并给出了信号处理电路．实验表明该系统测量范围宽、测量精度高、结构简单．     

Determination of the linear equations of position-sensing detectors for small motion measurement systems

Small motion measurement systems are widely used in industry measurement fields to measure small positional/angular motions. These systems usually consist of two parts: a measuring assembly and a reference assembly. The position-sensing detectors (PSDs) are embedded in either measuring assembly or reference assembly to sense the variations of laser light incidence points when there are any small positional/angular motions. To use these systems, it is necessary to determine the linear equations of PSD readings, which relate the six-degrees-of-freedom small positional/angular motions and PSD readings. The purpose of this paper is to derive these equations based on the paraxial raytracing method. Two measurement systems are used as illustrative examples to validate the proposed methodology. The methodology of this study will be useful for system design of PSD-based measurement systems and their applications.     

位置敏感探测器定位分析和应用研究

位置敏感探测器是近几年问世的一种新型位置探测器,可直接用来测量角度、高度、距离及运动。本文论证了二维位置敏感探测器定位原理,导出了位置坐标的电流函数表达式,给出了相应的检测电路框图,提出了用位置敏感探测器进行人体三维运动测量的系统方案,并就信号的产生、提取及数据处理问题进行了讨论,最后估算了有关系统参数。     

Measurements of detector nonlinearity at 193 nm

We have developed a measurement system based on a correlation method to characterize the nonlinearity of a detector's response over a large range of laser pulse energy. The system consists of an excimer-laser source, beam-shaping optics, a beam splitter, a monitor detector, a set of optical filters, and the detector under test. Detector nonlinearities as large as 10% or greater over an entire measurement range at an excimer-laser wavelength of 193 nm are observed. The measurement range of the current system is approximately 300 nJ to 50 mJ of laser pulse energy at the detector under test. The typical expanded measurement uncertainty of nonlinearity is 0.6% (k = 2).     

A universal angle-measuring instrument

The working principle and design are described for a universal autocollimation angle meter, which is intended for checking various geodetic instruments (geodetic levels, theodolites), and also other instruments with small measurement ranges (levels and autocollimators). The basic mechanical characteristics are given. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 10–12, September, 2006.