机动车前照灯校准器光轴角零位示值误差超差的调整

本文对机动车前照灯校准器光轴角零位的调整作了探讨。     

汽车前照灯检测仪校准器检定系统的设计

本文介绍了一种以面阵CCD成像技术作为测试方法的汽车前照灯检测仪校准器检定系统。此系统采用多维精密可调工作台 ,利用计算机数字图像处理技术及VC 编程实现自动测量被测校准器的发光强度、远光光束中心、近光明暗截止线转角坐标以及光轴偏移角等特征参数的目的。其优点是测量精度高 ,重复性好 ,实现了测量自动化     

机动车前照灯检测仪存在的问题

在日常检定工作中.笔者发现几乎所有的被检前照灯检测仪都不能一次通过检定,其中最突出的问题是近光明暗截止线转角、发光强度以及光轴偏移角这3个技术指标.均须经过对其系数进行调整后才能符合规程的规定.这种现象不禁会使我们产生这样的疑问:周期检定内的前照灯检测仪为什么会"带病"运行?     

机动车前照灯检测仪光轴偏移值(角)示值误差测量值的不确定度评定

本文介绍了机动车前照灯检测仪光轴偏移值(角)示值误差测量结果的不确定度评定及分析的方法。     

机动车前照灯检测仪检测稳定性评价方法

目前我国绝大多数机动车检测机构使用全自动前照灯检测仪进行灯光检测,自动设备的工作稳定性将直接影响其测量准确度与检测效率。实验选取全新进口车作为稳定光源,按照GB 7258—2012的检测方法进行多次重复实验,并基于设备检定结果与JJG 745—2002检定规程制定全自动前照灯检测仪检测稳定性评价方法,用该方法对两套自动检测仪进行了评价。     

电子屏幕法机动车前照灯检测仪的检定

机动车前照灯检测仪作为判定机动车灯光发光强度是否合格的仪器,国家制订了JJG745-2002《机动车前照灯检测仪检定规程》,该规程是基于CCD摄像成像原理进行设计,未涵盖电子屏幕法全自动机动车前照灯检测仪,本文从电子屏幕法的测量原理出发,讨论如何实现该仪器的量值溯源。     

机动车前照灯检测仪检定中相关问题探讨

分析了目前汽车前照灯检测合格率低的原因并提出了解决办法,并对汽车前照灯检测仪检定中用线绳对正及采用透明水管检查校准灯激光发生器发射激光束是否水平等实际问题进行了探讨。     

机动车前照灯检测仪检定和标定中的注意事项

针对机动车灯光检测仪的标定和检定问题的使用现状,文章提出了实际工作中具有可操作性的注意事项。文章陈述了方法产生的背景,通过图解对方法进行了介绍。     

机动车前照灯检测仪测量结果不确定度评定

文章从机动前照灯检测仪(光强、偏移角)测量方法出发,分析评定其测量结果的不确定度,为检定和校准其他类似仪器提供科学的测量校准方法。     

激光经纬仪在检定机动车前照灯检测仪中的应用

根据机动车前照灯检测仪及校准器的特点,分析了校准器位置对前照灯检测仪检定结果的影响.详细介绍了激光经纬仪在前照灯检测仪检定中的几种应用方法,使复杂、费时的校准器安置,变得操作简单.并通过实验数据,证明该方法调整精度高,速度快;且安置重复性好.     

A computerized measuring system for certification of phase calibrators

Translated from Izmeritel'naya Tekhnika, No. 2, pp. 41–43, February, 1991.     

基于机器视觉的前照灯仪校准器检定装置

目前对汽车前照灯仪校准器的人工检定方法存在着检定效率低、测量不确定度大的缺点,而利用机器视觉技术改造后的检定装置则存在着CCD芯片本身无法进行量值溯源的原理缺陷.建立了一套结合机器视觉技术与传统检定方法的检定装置,根据机器视觉分析得到校准器光型特征,利用转台测量光轴角参数及照度计测量发光强度参数,可以实现高准确度、高效率的检定.实验结果表明,该装置的性能完全满足检定前照灯仪校准器的要求.     

A novel method for measuring direct compressive properties of carbon fibres using a micro-mechanical compression tester

A novel method has been developed for measuring direct compressive properties such as strength and elasticity of a series of mesophase-pitch-based and PAN-based carbon fibres about 10 m in diameter by uniaxial and transverse compression tests using a micromechanical tester. The fibres were shaped into cylindrical specimens, with their size ratio of length to diameter kept at about 2 to 3, by separating them from a thin film made by polishing the cut faces of a strand of carbon fibres with epoxy resin as a matrix. Individual cylindrical specimens were stood up or laid down on a glass plate without any fixer for the measurements of axial and transverse compression properties of fibres, respectively. The fibres exhibited non-linear elasticity, with the compressive modulus decreasing with compressive deformation. The direct axial compressive strengths of pitch-based carbon fibres were found to be marginally lower than the indirect ones, whereas there was no significant difference between the two strength values for PAN-based fibres. The pitch-based fibres exhibited smaller average values of axial compressive strength than the PAN-based fibres. The transverse compressive strength, which decreases with an increase in elasticity of carbon fibres, exhibited a considerably lower average value than that of the axial compressive strength. Further, the axial compressive strength was found to be smaller than the direct tensile strength for the fibres.     

基于成像测量的车辆前照灯配光屏幕标定方法

根据基于面阵CCD摄像机成像测量的车辆前照灯配光性能测试系统的特点,提出一种成像测量与图像处理相结合的车辆前照灯配光屏幕照度测试靶标标定方法。该方法直接利用车辆前照灯配光性能成像测试系统对车辆前照灯配光屏幕上不同照度测试位置处分别放置的直线靶标进行成像,获取各直线靶标图像。在图像处理中,采用图像差分法及二值化方法提取各直线靶标,通过对各直线靶标的细化操作,获得各单直线图像,最后,采用本文提出的“粘贴”和“裁剪”方法将各单直线图像融合成一幅车辆前照灯配光屏幕照度测试位置靶标图像。该标定方法不仅能在车辆前照灯配光性能成像测量中使配光屏幕上的照度测试位置用照度测试位置靶标图像中对应的成像位置来定位,而且还能保持配光屏幕的均匀反射率特性。因此,该标定方法有利于实现配光屏幕上各处照度的同时成像测量。实验结果得出:文中标定系统的标定准确度为93.53%,符合车辆前照灯配光性能测试的要求。     

A model for evaluating the effectiveness of motor vehicle inspection programs

A statistical model for the evaluation of the effectiveness of motor vehicle inspection programs in reducing highway crashes is presented. The model is based on the assumption that the waiting time between highway crashes follows an exponential distribution. Since highway crashes are relatively rare events, it is assumed that the length of the study period is such that censoring occurs. Under these assumptions, maximum likelihood estimates of the mean waiting time θ until a crash for the non-inspected (inspected) vehicles is obtained and the corresponding test statistic is derived. As mechanically-caused accidents are but a small part of the overall accident picture and since inspection should only affect this portion, sample size requirements are investigated for various combinations of θ, Δ (increase in average time until a crash due to the effect of inspection), L (length of study period), and = β (probability of Type I error equalling probability of Type II error). For reasonable Δ, the sample required is indeed sizable.