激光跟踪扫描曲面测量的自适应算法研究

针对自由曲面壳体的测量问题,研究了非接触测量时激光束跟踪测量高精度自由曲面壳体的一种自适应测量算法。从测量速度和精度两方面考虑,提出采用圆弧切线外插算法控制激光束跟踪扫描,实现曲面的自适应跟踪测量。采用该算法在三坐标测量机上用激光束跟踪快速扫描测量电力安全帽实物样件,并对其进行实物原型的数字化处理,完成了电力安全帽反求工程测量任务。测量实验表明采用该算法跟踪和测量精度高,测量速度快。     

空间自由曲面的非接触扫描测量

研究用程控三坐标测量机非接触扫描测量空间自由曲面。由程控三坐标测量机、ＰＨ９／ＰＨ１０回转体和ＬＢ—１２型非接触激光测头构成测量系统;用实时跟踪法控制测头运动;以ＰＨ９／ＰＨ１０回转体为核心,建立扫描回转测头系统的数学模型,实现一次性标定转位扫描测头;进行数据规则化处理。实验表明,扫描测量的综合误差不大于±０．０７ｍｍ。     

图像测量技术在金刚石滚轮轮廓曲面测量中的应用

<正>1金刚石滚轮轮廓曲面参数测量的现状金刚石滚轮是一种高精度的金刚石修整工具,主要用于汽车、发动机及零部件、轴承、纺织机械、齿轮等行业成型磨削制造。金刚石滚轮具有轮廓曲面复杂、加工精度高的特点,但是目前对金刚石滚轮轮廓曲面的测量大部分采用以下两种方法:(1)转移复制—投影仪测量将被加工的金刚石滚轮磨削一个砂轮,再用砂轮磨削一个量块,将量块放到光学投影仪与模板进行投影比对。(2)转移复制—轮廓仪测量     

大型曲面形状激光自动测量技术研究

讨论大型曲面形状激光自动测量系统的原理.其基本思想是让非接触光电测头与被扫描测量的曲面始终保持一个恒定的Z方向距离,使测头的扫描轨迹即为被测曲面形状.给出该系统的完整组成,并用系统对一个1∶5轿车车身的油泥模型进行实测,证明系统能在1200mm的长度内达到±0.08mm的测量精度,其测量时间为10min.     

曲面激光测量装置的研究

本文提出了一种激光扫描双三角曲面测量方法，目标光点分别通过两套成像系统成像在两个光电接收器ＣＣＤ上，根据光点在ＣＣＤ上的成象位置从而得出光点的二维坐标，再用多面棱镜完成光点扫描，从而完成曲线测量，然后，由数控工作台带动测量平台上、下移动，完成曲面测量。     

曲面形状测量中二维激光测量头的设计

详细阐述了二维光学测量的原理,指出了传统单三角测量中像点位移和表面起伏的关系的不准确性,推导了光学测量头各器件之间的精确关系,给出了测量范围和像点的关系,最后根据设计实例说明测量装置调节的可能性和调节方法     

自由曲面的光切断测量法

介绍自由曲面的光切断测量法的测量原理,硬件系统,软件系统应具有功能,以及数据输出形式.     

光切法扫描测量策略及其数据合成

根据常见测量对象的几何特征及光切法三维轮廓测量特点，设计了两种测量系统结构方案，并重点介绍了四轴卧式系统四种扫描测量策略及其数据台成方法，最后给出了实物测量结果。     

光切法在脚型测量技术中的应用

光切法是一种三维曲面非接触测量方法,具有测量速度快,成本低,系统组成灵活等优点.介绍了如何将光切法用于脚型测量以及测量系统的设计、组成、扫描原理、数学模型、图像预处理等问题,提出了采用对称放置的双CCD技术.实验结果表明该系统具有良好的实用价值.     

在机测量激光测头位姿的线性标定

针对在机激光扫描测量中激光测头安装位置和姿态引起的测量误差,提出了一种适用于在机激光测量的测头标定方法。构造了在机激光扫描测量原型系统,建立了激光测头随机床运动的测量模型;通过多角度扫描标准球球面拟合球心,给出了一种线性求解测头安装位姿参数的算法,避免了非线性优化求解中的大量计算和不稳定问题。分析了测量过程中机床各个轴的运动误差对测量结果的影响,建立了误差模型,并给出补偿机床系统误差的方法。实验显示,对直径已知的标准球进行测量时,测头在不同摆角测得的标准球直径误差小于0.05 mm,误差补偿后球心位置误差减小了83%。实验结果验证了该标定方法的可行性,以及机床误差对测量精度影响的模型及补偿方法的正确性。     

内六角圆柱头螺钉参数化的实现及应用

主要介绍如何在Pro／E下实现内六角圆柱头螺钉的参数化设计及在其它软件中的分析应用,通过参数来控制模型尺寸,完成参数化设计后使用族表来实现模型设计的标准化和系列化。族表完成后,进入该零件只需选择族表中对应的任一数据,则得到该数据下的零件模型,而不需重新根据尺寸构建模型。     

基于无衍射姿态探针和全站仪组合测量空间隐藏坐标

针对大尺度空间中构件特征隐藏区的空间坐标测量,提出了一种基于无衍射光束的测量探针,并将该探针与全站仪结合构成了空间坐标组合测量系统。介绍了探针姿态测量系统和组合测量系统的结构与原理。测量时,首先将探针测头接触于被测点,并用全站仪或激光跟踪仪瞄准探针的光学系统,测得探针的空间位置坐标。接着,使用探针将测距激光通过axicon透镜变换为无衍射光,并由CCD摄像机获得图像。由无衍射光的中心一对一映射激光的入射方向,通过无衍射光图像定中计算,获得探针的水平角和俯仰角。最后,通过电子倾角仪测得探针滚动角;联合测得各姿态角和位置坐标,通过坐标变换,计算得出被测点的空间坐标。实验显示,该探针的姿态角测量精度为1mrad,组合测量空间位置偏差为±1mm,表明基于无衍射光束的探针与全站仪所构成的组合测量系统可满足大尺度空间中特征隐藏区空间坐标测量的要求。     

暗杆楔式闸阀阀杆密封结构改进

阐述了一种带压可更换阀杆密封填料的暗杆楔式闸阀结构，分析了其工作原理和性能。     

Quantitative atom probe analyses of rare-earth-doped ceria by femtosecond pulsed laser

We have investigated the irradiation conditions of femtosecond laser pulses for quantitative atom probe analyses of rare-earth (RE) doped ceria. The influence of laser wavelength, power, pulse frequency, as well as specimen temperature on mass resolution and background noise of atom probe mass spectra were investigated. Furthermore, quantitative atom probe analysis of yttrium distribution in Y-doped ceria was carried out with the optimized evaporation conditions. The distribution of yttrium was found to be uniform within the grains, but they were confirmed to be segregated at grain boundaries.     

Pulsed laser atom probe analysis of semiconductor materials

As the size of semiconductor devices is reduced the active volumes of material in each device is also decreased. Under these circumstances it becomes more important to understand the microchemistry of semiconducting materials, as small fluctuations in composition can dramatically affect both the operation of the devices, and of the contacts to semiconductors. Atom probe microanalysis has been shown to be able to analyse the microchemistry of metallic materials with plane-by-plane resolution, and by using a pulsed laser to replace the more conventional voltage pulses the analysis of semiconducting and insulating materials becomes possible. The pulsed laser atom probe has been shown to give very accurate chemical analysis of the stoichiometry of extremely small volumes of III-V compound semiconductors, and the composition of the interfacial layer between silicon dioxide and silicon has been identified as SiO of thickness about 0.3 nm. It has been shown to be possible to prepare specimens for analysis from thin films of semiconductors, thus allowing the microanalysis of a wide range of materials that are deposited in thin film form.     

A differential laser autocollimation probe for on-machine measurement

An optical probe based on the principle of differential laser autocollimation has been developed for the purpose of on-machine measurement of mirror shapes. The probe is so compact that it can be mounted on diamond lathes. It can be rotated by a stepping motor about an axis perpendicular to the optical axis of measurement, and has been used to measure mirror shapes on an apparatus that imitates the conditions of an on-machine measurement system. The probe can reduce remarkably the measurement errors due to vibrational and thermal noises that could not be avoided previously in on-machine measurement. Estimating from repeatability, accuracy is better than 0.1 μm in measurement of a parabolic curve whose depth is >1 mm and length is ≈ 100 mm.     

纳结构的连续激光复合微纳探针刻划加工

为了加工形貌稳定且尺寸尽可能小的纳结构,建立了一套连续激光复合微纳探针的加工系统,并研究了光纤探针导光的连续激光辐照微纳探针的近场增强效应以及该系统的加工性能。首先,根据表面等离子体激元理论仿真分析了激光辐照原子力显微镜(AFM)探针的近场增强因子,并研究了微纳探针的针尖温度场和针尖热膨胀。接着,搭建了基于光纤探针导光的连续激光复合微纳探针的纳结构加工系统。最后,对聚乙烯片状材料样品进行了纳结构加工。结果显示:加工得到的纳米点尺度为200nm左右;纳米线的尺度为30~40nm。结果表明:光纤探针导光连续激光复合微纳探针系统避免了复杂的空间光路结构,是一种成本低廉,结构简单的系统,能够实现纳结构的加工。     

基于激光三角测量原理的轨距检测系统研究

轨距是轨道几何尺寸中的一个重要参数,及时掌握轨距信息对保证行车安全具有重要意义.基于激光三角测量原理研发了一种安装于路轨两栖综合检测车上的轨距检测系统.该系统使用2组共6台二维激光扫描传感器获得左右钢轨断面轮廓,利用基于CPLD的同步信号触发模块保证各传感器数据同步.通过对采集的钢轨断面轮廓数据采用基于不连续度的自适应滤波和钢轨弧形区特征提取算法,实时提取轨距特征点并计算显示当前断面轨距值.实验结果表明,该轨距检测系统可实现轨距参数的非接触式动态实时测量,检测车运行速度为40 km/h时钢轨断面采样间隔3.7 mm,轨距检测精度±0.8 mm.     

Nanoscale fretting wear study by scanning probe microscopy

Nanoscale fretting wear was studied by using scanning probe microscopy (SPM) and a newly proposed unified approach of slip index. The production of SiO₂ colloidal probes and the SPM calibration are described. Partial and gross slip fretting with displacement amplitudes from 5 to 500 nm were used for the study. Friction coefficient and nanowear results are presented showing a substantial increase of the friction at the transition from partial to gross slip and a significant difference between damaged surfaces in the two fretting regimes.