基于MEMS陀螺的压气机静子叶片安装角度测量系统研究

介绍了一种基于MEMS陀螺的高精度压气机静子叶片安装角度测量系统的设计方案。从测量需求入手,利用双轴MEMS陀螺角度传感器和基准工装对小空间、高精度的静子叶片安装角进行测量,推导了倾角测量算法,进行了误差分析,并设计了基于MEMS陀螺的角度测量系统。     

雷达液位计在克拉2气田的应用

文章介绍了克拉2气田在用的Rosemount 3300系列和5600系列导波雷达液位计的测量原理、特征、安装方法、误差来源等,对油气田使用雷达液位计测量储罐、分离器等设备的液位具有指导意义.     

基于安装误差的导引头隔离度测量值修正

为提高红外导引头隔离度的测量精度,结合导引头测试系统原理,分析红外导引头安装误差对隔离度测量值的影响。利用多体建模理论构建红外成像导引头安装误差模型,推导由安装误差所引入的导引头视线角速度测量误差,并对该误差所导致的导引头隔离度测量值的误差进行了仿真分析。最后,利用误差模型对隔离度测量值进行补偿,并利用半实物仿真系统进行实物测试,得到补偿前隔离度测量值为1.034%,由安装误差引起的测量值误差为0.129%,补偿后隔离度值为0.902%。测试结果表明了该方法的可行性,对解决红外成像导引头隔离度的高精度测量具有参考意义,为红外成像导引头的试验评估提供了理论基础与技术保障。     

一种星敏感器安装误差自动化测量方法

针星敏感器安装误差的精确标定,该文提出基于平台式惯性/星光组合导航系统中,星敏感器相对惯性坐标基准的安装误差自动化测量方法。首先基于光电自准直仪测量方式,建立安装误差测量的数学模型,并通过仿真验证模型的有效性。开发一套自动化测试系统,利用高精度的光电测角仪模拟星光,将星敏感器主光轴对准星点,输出星点坐标信息,自准直仪测量标准六面体的姿态,通过与星敏感器坐标对比和软件自动解算得到星敏感器相对标准六面体的安装误差。试验数据能达到5″内的测试稳定精度,证明该方法可准确测量出星敏感器的安装误差,且测试稳定性好,已应用于工程精密测量。     

非接触法在线测量和调整圆柱轴线同轴度研究

本文对圆柱同轴度的测量原理、圆柱同轴度调整方法作了详细分析.选择高精度激光位移传感器LK031来实现同轴度测量,由自编软件给出调整量,对测量仪器的误差分析表明,测量方案满足测量要求.     

圆感应同步器安装误差的电气测试方法

圆感应同步器是高精度角度传感器件,要求很高的安装精度。安装误差不仅降低感应同步器的测量精度,而且降低有效电势和增大剩余电压,造成电子编码器工作不稳定。本文所介绍的安装误差的电气测试方法借助定、转子绕组间耦合电势判断各绕组相对于回转轴线的同轴度误差和垂直度误差,以及对应的几何位置,为准确地安装提供依据。该方法不仅用于计量室,而且可用于使用现场。     

三峡升船机高精度金属结构埋件安装技术

针对三峡升船机工程金属结构一期及二期埋件的布置特点,并结合现场施工环境,对高精度安装作业进行了详细分析,提出了适宜三峡工程金属结构埋件安装的多种施工方案,并在三峡工程中得到广泛成功应用,解决了施工中埋件变形控制、快速高精度调整定位和高精度测量保障等技术难题,为同类工程的施工提供了借鉴。     

雷达-光电经纬仪联合定位模型及误差分析

在现代靶场测量系统中,将不同测量设备测量数据进行融合处理以提高系统的综合测量水平和设备的使用效率。利用部署在光电经纬仪附近的雷达,建立雷达-光电经纬仪联合定位模型,将测角信息和部署在其附近雷达的测距信息进行数据融合,可以得到目标相对于经纬仪的距离,从而确定目标的空间三维位置;分析了定位模型的主要误差来源和典型情况下的误差情况。其结果表明,在典型情况下雷达经纬仪联合定位模型距离定位误差与雷达测距误差基本相当。     

成品油检尺与雷达液位计测量的误差分析

对人工检尺和雷达液位计的计量误差进行了对比研究,建立了两者的测量不确定度模型,并分别计算了两者的测量不确定度。分析了雷达液位计测量特点、局限及误差的主要影响因素,提出相应的改进措施,实践表明能够有效提高雷达液位计的测量不确定度。     

一种微机控制的多测头凸轮轴测量系统

本文介绍一种由机械装置，高精度圆光栅编码器，光栅位移传感器，微型计算机，接口控制电路等组成的多测头凸轮轴测量系统，该系统安装调整方便，定位准确，测量精度高，操作简单，工作可靠，能快速实现对凸轮轴的自动测量。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.     

Numerical study of methods of linearization of the output characteristics of radio-frequency sensors of the level of dielectric media

Different constructions of the sensing elements of radio-frequency level sensors based on sections of long lines are numerically investigated by means of the Matlab program for the purpose of minimizing the measurement error caused by the nonlinearity of the output characteristic. It is shown that the nonlinearity is lowest for U-shaped designs. The nonlinearity factor KN may be regulated by varying the capacitance of a correcting capacitor connected to the input of the sensing element and (or) the length of one of the sections of the long line. In selecting an optimal capacitance of the correcting capacitor KN ≤ 0.15% for control media with dielectric permittivity in the range 2.2–30.     

Possibilities of Decreasing the Errors of Determination of the Height of the Pole of a Sessile Drop of Melt

We analyze the possibilities of decreasing the errors of measuring the height of the pole of a sessile drop of melt above its equator by determining the position of the equator according to the midpoints of vertical chords of the image of the drop. The optimal distance between these chords and the edge of the image of the drop is chosen within 10–20% of the radius of the equator. The proposed method guarantees the same level of errors of evaluation of the height of the pole and the radius of the equator, which enables one to substantially increase the accuracy of evaluation of the capillary constant and the surface energy of the melt according to the geometric parameters of the sessile drop.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.