超精密二维测量定位系统评定及误差分析

超精密测量定位是实现现代超精密加工的重要环节.以宏微结合式的超精密二维定位平台为基础,组建了基于光谱共焦位移传感器的超精密二维测量定位系统,介绍了该系统的组成与功能实现方法.利用高等级量块对系统进行二维校准,再将该系统应用于二维尺寸的测量,分析了测量误差,并进行了测量不确定度的评定,试验获得该测量系统X、Y方向的测量不确定度分别为89 nm和87 nm.研究表明该超精密二维测量定位系统初步达到了纳米级测量效果.     

超精密二维工作台自标定技术研究

基于刚性运动方程和非线性最优化方法提出了一种超精密二维工作台自标定模型,研究了随机测量误差在自标定过程中的传递特性,在此基础上提出了超精密二维工作台自标定算法。给出了一个应用实例,验证了该算法的可行性和有效性。     

基于二维影像测量的全自动检测装置研发

小型回转类零件尺寸小、待检特征多样,通常只能采用手工检测,存在检测效率低、耗时长等问题。通过分析此类零件的检测需求和待测特征,采用二维影像测量的方式,研发了一款集自动上料、快速测量、结果判定及分拣功能于一体的全自动检测装置,可在实现多特征的同时进行高效测量。通过更换不同的上料机构,还可实现对同类零件的自动化检测。该装置已正式投入现场生产检测,使用效果良好,为小型回转类零件的批量自动化检测提供了技术保障。     

基于浮力的二维轮廓测量及其重构算法研究

提出一种基于液体浮力的适于二维轮廓测量的计算模型和测量方法,阐述了该方法的测量原理与重构算法,由阿基米德定律,利用电子天平逐层测算被测实体浸入液面不同深度时所受浮力,通过计算相应片层的质量、重心等信息,得到能表征被测实体二维轮廓的二进制图像,仿真计算结果证明该方法是有效和可行的。     

基于复合位姿的二维自校准研究

自校准与校准相比,无需精度等级高于被校准对象的标准样板,能以较低的条件成本实现精密测量仪器系统误差的校准。二维自校准中的标准样板常采用初始、相对旋转和平移的传统三位姿组合。位姿之间相互独立且所有位姿变换均以初始位姿为基础。采用旋转和平移两种位姿复合后的位姿,能避免两次位姿变换之间必须将标准样板回归初始位姿的冗余操作,简化了二维自校准流程。基于复合位姿的二维自校准经仿真实验证明能在模拟噪声环境中有效分离被校准对象的误差,其不确定度与传统非复合位姿组合的相等。复合位姿的引入不影响二维自校准的噪声抑制能力。在影像测量仪上实施二维自校准实验,采用包含复合位姿的三位姿组合的二维自校准分离的工作台系统误差接近传统三位姿组合。两种位姿组合对应的工作台系统误差结果相差0.167μm。另外通过采用包含复合位姿的四位姿组合的实验结果,进一步论证了基于复合位姿的二维自校准效果。     

基于FDTD的探地雷达典型形状目标二维散射仿真

探地雷达以其无损、高效、使用灵活、分辨率高等优势在工程物探领域得到了广泛应用,研究探地雷达回波的正演数值模拟将有利于提高对探测目标解释的精度和准确性.采用时域有限差分法和完全匹配层边界条件建立了探地雷达正演模拟方程,利用该方程对地下层状结构、矩形模型和球状模型的进行了正演模拟,结果表明:建立的数学模型可以实现探地雷达典...     

平面度坐标测量的不确定度计算

目前的坐标测量只是给出平面度最小二乘检验的结果,并没有给出检验结果的不确定度.根据平面度最小二乘检验的基本原理和ISO/TS 14253-2给出的不确定度传递公式,提出了一种平面度坐标测量的不确定度的计算方法.该方法的特点是将平面方程的系数看作一个随机向量,通过计算该随机向量的均值和协方差矩阵来确定平面方程和平面度的检验结果及其不确定度.这不仅保证了平面度检验结果的完整性,而且符合新一代产品几何规范(GPS)标准的要求,从而可以提高工件检验的准确性.实验结果表明,根据平面度最小二乘检验的结果及其不确定度,可以根据ISO 14253-1给出的判定原则定量地判定平面是否合格.     

基于二次测量的曲面反求自适应采样方法研究

针对叶片CAD模型未知的情况,提出一种基于二次测量的曲面反求变弧长自适应采样方法。通过三坐标测量机测量反映叶片曲面形状的关键几何要素,重构曲面初始模型;基于初始模型获得的叶片曲率信息,确定采样方向和进给方向;基于变弧长自适应采样方法,使用三坐标测量机对叶片采样;基于获得的采样点坐标信息,反求出CAD模型。通过模拟仿真试验,在采样点数目能够准确反映曲面曲率的情况下,相对于采用等弧长、等弦弧比、等弦弧差自适应采样方法,采用变弧长自适应采样方法的曲面拟合精度明显提高。     

基于平面驻波磁场的二维位移传感器 测量原理与结构优化

在芯片制造、智能制造、航空航天等领域,精密平面定位迫切需要平面两维度位移的同步独立精密测量。本文提出一种基于电磁感应原理的平面位移传感器,由动阵面和定阵面组成。定阵面由m×n个平面螺旋线圈阵列串联而成,通入交变励磁电信号时在测量平面产生平面驻波磁场。动阵面由四个螺旋线圈以2×2矩阵形式排列,感应出振幅随x轴和y轴位移变化的四路调制信号,并利用Cordic算法求解两维度位移量。本文首先介绍了传感器的工作原理,对电磁模型进行有限元分析,并对位移解算算法进行数值模拟。根据仿真结果对测量误差进行分析溯源,优化传感器结构。制作传感器样机开展了实验验证,验证了传感器结构和位移解耦方法的可行性。实验表明,传感器在节距内最大误差为48.7μm,分辨率为0.317μm,在147 mm×147 mm量程范围内,传感器线性度达到0.15%,为高精度电磁感应式平面二维位移传感器的进一步发展提供了理论支撑和实验指导。     

基于通用Dombi算子的测量不确定度传递方法研究*

随机模糊变量RFVs法是近年来提出的一种基于可能性理论的测量不确定度评定和表示方法。RFVs法应用t-范数传递不确定度随机分量,是传统概率论方法的近似。针对Frank t-范数传递多个随机分量时近似误差累积变大的问题,提出使用二参数通用Dombi算子传递随机分量。首先简单介绍了RFVs的含义;然后说明了最优t-范数及其参数的选择方法,得到了GDO的最优参数,并用于获得联合可能性分布,结果表明GDO对于合成随机分量有很大改善;最后将GDO用于有功功率测量不确定度评定,并与Frank t-范数、传统GUM法和实验数据比较,使用GDO得到的置信区间能够很好地近似传统GUM法和实验数据分析结果。具有2个参数的GDO具有更大的灵活性,可以在传递多个不确定度随机分量的情况下获得满意的结果。     

A large‐field polarisation‐resolved laser scanning microscope: applications to CARS imaging

Laser‐scanning imaging techniques are frequently used to probe the molecule spatial orientation in a sample of interest by exploiting selection rules depending on the polarisation of the excitation light. For the successful implementation of these techniques the precise control of the polarisation at the sample level is of fundamental importance. Polarisation distortions induced by the optical elements are often the main limitation factor for the maximum size of the field‐of‐view in polarisation‐resolved (PR) laser‐scanning microscopy, since for large scanning angles the polarisation distortions may mask the real sample structure. Here we shall demonstrate the implementation of large‐field‐of‐view PR microscopy and show PR CARS imaging of mouse spinal cord thanks to a careful design of the laser‐beam optical path. We shall show that this design leads to strongly suppressed distortions and quantify their effects on the final images. Although the focus of this work is on CARS imaging, we stress that the approaches described here can be successfully applied to a wide range of PR laser‐scanning techniques.     

基于激光扫描的足部三维测量仪设计

个性化鞋楦设计是社会发展的必然趋势,足部测量仪的研制成为了一个重要课题.提出了个性化足部扫描测量仪的设计方法,介绍了仪器的测量原理以及标定方法,设计出控制系统、光学系统、移动平台和图像采集模块来实现快速足部扫描.经过自行开发的软件控制系统执行图像提取与数据分析,即可在短时间内重建出所测量的足部轮廓.最后,对足部进行了实际扫描,该过程可在10s之内完成,测量误差小于0.5%.得到了很好的结果,满足工业设计的要求.     

快速大面积测量用原子力显微镜扫描速度对测量结果的影响

构建了一种可快速大面积测量光栅表面微结构的原子力显微镜(AFM)系统,研究了不同扫描模式下扫描速度对测量结果的影响。分别测量了微悬臂探针在恒高模式与恒力模式下的频谱,获得了这两种模式下微悬臂探针的有效带宽。基于恒高模式与恒力模式,在不同扫描速度下分别测量了光栅微结构表面上的一条直线与一个圆周,进而分析了扫描速度对测量结果的影响。基于该AFM系统,采用恒高模式下不失真扫描速度对光栅微结构表面进行了快速、大面积三维形貌测量实验。实验结果表明:测量光栅微结构表面上直径为4.0mm的圆形区域所用时间仅为40s。当扫描速度不超过微悬臂探针有效带宽所对应的速度时,所构建的AFM系统可无失真地实现微结构表面的快速、大面积测量。     

Time resolved 2D concentration and temperature measurement using CT tunable laser absorption spectroscopy

In this study, the noncontact and simultaneous 2D temperature and concentration measurement method has been developed to elucidate the reaction characteristics and improve the relevant simulation code. The technique is based on a CT method using absorption spectra of molecules such as H₂O, NH₃ and CH₄. The CT Tunable diode laser absorption spectroscopy (TDLAS) method using 16-path laser beams was applied to measure 2D temperature, NH₃ and CH₄ distributions in engine exhausts and oscillating flames. Simultaneous and time resolved 2D temperature, NH₃ and CH₄ distributions were successfully reconstructed using a set of 16-path absorption spectra. Since CT TDLAS has a potential of kHz response time, this method enables real-time 2D temperature and species concentration measurements in various industrial processes including engine applications.     

一种用于三维测量的边缘拟合插值算法

提出一种用于三维体数据体积、表面积测量的断层问边缘拟合插值算法.该算法首先对每一切片找出其轮廓线的几何彤心,将边缘点坐标转化成极坐标;之后根据ρ-θ的关系埘边缘点进行拟合插值,在层间边缘点建立一一对应的关系,最后通过对相邻断层间匹配边缘点极坐标中的ρ进行插值,从而生成中间层的边缘点的极坐标.与其他插值算法相比,该算法只生成并记录各断层的边缘点,减小了数据冗余,插值速度快,且精度好.在三维测量的实验中证明了该算法相对于其他插值算法在速度和精度上的优势.     

Acoustic CT system for temperature distribution measurement

In this paper,a measurement method for crosssectional temperature distribution is addressed. A novel method based on an acoustic CT technique is proposed. Specifically,the temperature distributions are estimated using the time of flight data of several ultrasonic propagation paths. The times of the flight data contain both temperature and wind effect,and the method to select only temperature component is introduced. A filtered back projection method is applied to reconstruct the temperature distributions from the time of flight data. An experimental system was designed and fabricated to realize simultaneous temperature and wind velocity distribution measurements. Through this system,the effectiveness of the proposed measurement method is confirmed.     

Mapping oxygen-induced temperature patterns of round bale silage based on 3D stepwise-profiling measurement

Abnormal rise of temperature in silage is regarded as a signal of aerobic deterioration caused by the permeation of atmospheric oxygen into the silage, which indicates the growth of lactate-assimilating yeasts and energy release. Although baled silage has distinct advantages over other forms of silage, the high surface-area to volume ratio of the bale leads to a high risk of aerobic deterioration due to plastic cover damage. With an objective to spatially assess any aerobic deterioration within round-bales silage, we modified a bale-penetrometer that is capable of profiling temperature distribution. For each tested bale having a cylindrical volume of 2.154 m³, 72 path profiles including 504 stepwise measurements were made. Furthermore, two paths were re-profiled to check if the proposed invasive method has a significantly contaminative effect on the internal temperature field. The resulting R² = 0.9978 between the profiling data and the re-profiling data verified that the contamination due to the invasion of ambient air following the temperature probe penetration could be negligible. We presented two mapping methods, one for two-dimensional (2D) cross-sections and one for three-dimensional (3D) volumes. To demonstrate the applicability of the proposed method, six representative samples of round bales with varied damage to plastic covers were tested. All temperature patterns, generated in both 2D- and 3D-space, were informative and clearly interpretable. Therefore, we conclude that the tested measurement method can benefit advance of bale silage research and production.     

铸坯表面温度场测量仪的研究

基于面阵CCD(charge coupled device)的测温系统可以有效克服氧化皮对铸坯表面温度测量的干扰,近年来成为高温测量领域研究的热点。但CCD的非线性关系导致动态测温范围窄、低温段测量精度低。基于窄带带通滤光片建立了单光谱辐射CCD测温模型,据此研制了由滤光片、CCD、CCD信号处理器及DSP构成的铸坯表面温度场测量仪。通过一点标定和自适应调整光积分时间,扩展了CCD测温范围,同时改善了低温段的测量精度,使各温度段测量结果趋于等精度分布;采用4级流水线机制及DSP、工控机(industrial personal computer,IPC)2级数据处理结构,提高了系统的实时性;该仪器还具有暗电流补偿和以太网传输功能。通过黑体炉标定和现场测量,结果表明研制的测温仪满足铸坯表面温度场测量要求。     

在机测量线激光传感器安装位姿的全局标定

针对三轴数控机床激光测头安装位姿误差造成测量误差且不易调整和校准的问题,提出了一种在机测量线激光传感器安装位姿标定方法。建立了线激光在机测量系统的数学模型,通过机床运动带动线激光测头对标定基准点的空间位置进行测量,基于手眼标定原理给出了关于测头安装位姿参数的线性求解算法,完成了对测头安装误差的全局标定。考虑了机床定位误差对于标定结果精度的影响,采用蒙特卡洛模拟进行了误差分析。采用半径为35 mm的圆孔进行测量验证,实验结果表明,标定后圆孔测量误差为0.051 6 mm,测量精度提高了约96%,实验结果验证了该标定方法的有效性和可行性。     

Accuracy and noise analyses of 3D vibration measurements using laser Doppler vibrometer

The in-plane and out-of-plane vibration components are used for 3D vibration measurements. The latter can be calculated by using three laser scanning vibrometers (LSVs) or by moving a single LSV to three different locations. These vibration components are calculated from the vibration signals measured at each of the three locations and the angles between the local coordinates and the LSV locations. The accuracy of the in-plane and out-of-plane vibration components can be degraded depending on the measurement angle. In addition to accuracy, the noise contained in the LSV can be amplified depending on the measurement angle. Hence, it is necessary to implement an analysis methodology for the angles, which is conducted for 2D vibration measurements first before extended to 3D. Finally, experiments are performed for both 2D and 3D at small and appropriate angles, and the elicited results are compared to those elicited using a 3D accelerometer.