基于三坐标测量机的空间自由曲面非接触测量技术的研究

提出一种自由曲面的非接触自动测量方法。测量系统由三坐标测量机、ＰＨ１０回转体和激光三角测头组成。ＰＨ１０回转体带动激光测头回转实现对空间任意自由曲面的测量。利用激光测头在工作距离之外无信号输出这一特点进行曲面边缘提取,基于边界曲线在空间内均匀划分扫描网格,采取仿形跟踪措施实现测头的跟踪。实验证明该系统能自动完整快速测量四边曲面,测量精度优于６０μｍ。     

大量程自由曲面的自适应跟踪测量方法研究

提出一种利用激光位移传感器实现自由曲面自适应跟踪测量的方法。该方法基于闭环运动控制技术,通过由光栅位移传感器及精密移动线性机构组成的伺服随动系统自动调整激光测头位置,以跟踪被测曲面的起伏变化,保证激光位移传感器始终工作在其线性度较高的测量范围内,从而实现对大量程自由曲面的自动测量。实验结果表明:利用激光位移传感器在小测量范围内非线性误差小的特点,集成光栅传感器和伺服机构,可实现大量程自由曲面的高精度测量。     

同步规划测量式叶片免形状精密测头系统

针对叶片测量测头灵活性差、无法兼顾精度和效率的问题,提出了一种免形状、高精度测头系统技术方案。首先基于"同步规划测量"思想,研发了新型免形状光学测头系统,然后分析了系统的工作原理、理论模型和关键技术,最后进行了实验研究,验证了方案的可行性和测头系统的精度水平。研究结果表明,该测头系统在无需输入叶片理论模型数据和姿态精调的情况下,自动进行路径规划并同步完成叶片型面数据的采集。测点数据的采集全部在传感器基准距离附近完成,从而有效地限制了倾角误差,综合测量精度控制在10μm以内。该测头系统具有算法简单、高精度、免形状等特点,在叶片类空间自由曲面测量领域具有较好的应用前景。     

激光测头数控仿形跟踪控制算法

分析了曲面数控仿形加工的关键技术,针对基于激光非接触测量的数控仿形加工,提出一种测头速度控制算法,解决了复杂曲面高速、高精度仿形测量与加工的问题。     

基于CMM的曲面检测技术与测头半径补偿

1 引言 随着反求技术、快速原型等新技术的应用,三坐标测量机已发展成为设计、制造、检验一体化的重要单元.随着CAD/CAM技术的广泛应用,如何准确、有效地从实物样件上采集复杂三维曲面的数据,进而快速转换成三维数学模型,是逆向工程(RE)技术研究的关键问题,因此研究如何对自由曲面进行快速高精度的自动跟踪测量就显得尤为重要.研究对任意自由曲面进行快速高精度测量,使测头在工件表面快速移动,从而快速记录移动路径的坐标值,对实现逆向工程(RE)和加工中的质量控制都具有重要意义.     

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.     

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。     

非接触式曲面测头设计及精度试验研究

针对激光测头因测量范围小难以满足大量程自由曲面的高精度测量要求的问题,基于伺服运动控制技术,集成激光测头和光栅尺研制了一种非接触式测头。控制激光测头工作在线性度误差较小的中心范围内、而采用光栅尺反馈实现大范围的测量,详细介绍了系统的硬件及软件设计。试验数据处理结果表明,与激光测头相比,研制的非接触式测头测量范围扩大了1倍,而测量不确定度、修正值、线性度等精度指标并没有下降。     

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。     

高精度三维螺纹测量机接触式扫描测头动态特性研究

扫描测头是高精度三维螺纹综合测量机的核心部件,其动态特性严重影响了整机的精度.为了提高测量机的精度,对高精度螺纹三维尺寸测量线性扫描测头的动态特性进行了研究.首先分析了三维螺纹综合测量机用扫描测头的测量原理,然后建立了动态特性模型并提出了影响动态测量结果的因素,最后通过实验验证了这种测头结构的动态特性和测量处理方式的有...     

Fourier transform profilometry employing novel orthogonal elliptic band-pass filtering for accurate 3-D surface reconstruction

The article proposes a novel orthogonal elliptic band-pass filtering methodology in Fourier Transform Profilometry (FTP) for significant improvement of accurate 3-D measurement surface reconstruction with arbitrary object colors. Compared with phase shifting profilometry (PSP), FTP using fringe projection can achieve a general 3-D surface profilometry more efficiently by employing one-shot imaging. However, a challenging problem commonly encountered by FTP using fringe projection is its unreliable extraction of precise spectral information from the spectral domain especially when the spectral domain is complicated to process. Various filtering methods previously proposed in FTP have been proved unsuccessful or nonrobust. Thus, a new band-pass filter is developed from an adaptive orthogonal elliptic region to achieve higher accuracy of 3-D surface reconstruction. A comprehensive theoretical analysis is performed to investigate the physical measurement limits of the proposed method. The experimental results obtained confirm that the measurement accuracy of dimension and sphericity can be greatly enhanced when compared with that achieved by the traditional circular band-pass filter. The proposed method is proved to outperform all the other existing FTP band-pass filtering approaches. The maximum dimensional error measured can be controlled within 1.25% of the overall measuring height with various surface colors. However, it is also verified that the traditional three-step PSP can achieve slightly better measuring repeatability than the proposed method.     

基于红外测温的筒形锻件内外径在线测量

针对目前筒形锻件外形尺寸无法实现在线测量的现状,提出一种新的基于红外测温技术和激光扫描技术相结合的筒形锻件内外径在线测量方法,该方法中温度信息由红外双色测温系统测得,外径尺寸信息由激光扫描技术测得。对红外测温原理进行研究,根据测量现场的情况构建红外双色测温系统,减小现场恶劣环境和锻造过程中锻件表面氧化皮对测温造成的影响,提高了测量精度。在传热学的基础上推导筒形锻件导热微分方程,建立筒形锻件温度与尺寸的关系,结合锻件内外表面的温度信息和外径尺寸信息求得内径尺寸的大小,从而实现筒形锻件内外径尺寸的在线测量。通过试验验证该方法的可行性,同时可以满足现场测量的精度要求,从而解决筒形锻件内外径测量的瓶颈问题,在筒形锻件锻造现场有一定的应用前景。     

Location tracking scanning method based on multi-focus in confocal coordinate measurement system

Confocal microscopy is high precision and widely used method for topography measurement. The surface height information is obtained by peak extraction of the axial response signal (ARS) which axial tomography of the surface is required. Therefore, when scanning large-diameter surfaces with a confocal coordinate measuring system (CCMS), the relative horizontal scanning trajectory (RHST) between the confocal sensor and surface is repeated and time-consuming step motion, which greatly increases the measurement time. To improve the scanning measurement efficiency of CCMS, we propose a new location tracking scanning (LTS) method based on multi-focus. In the LTS method, the RHST is a continuous linear motion during the process of axial tomography, and the horizontal motional surface is located and tracked through a series of focuses to restore the ARS. A generatrix profile of a spherical surface is measured to verify the effectiveness of the proposed method, and the results show that the scanning measurement time can be reduced by more than 90% without loss of accuracy of the profile measurement.     

提高自由曲面透镜测量精度的迭代重构曲面算法研究

在提出的基于图像变换的光学透镜的表面面形测量方法中，建立了造代重构曲面算法。算法根据待测透镜光学表面在光学成像系统中的图像变换特性，重构出与待测透镜光学表面具有相同图像变换特性的数值三维曲面簇，利用造代方法从中筛选出与待测透镜光学表面面形完全相同的数值三维曲面，解决了测量精度不足的问题。实验结果表明，使用该算法所构建的数值曲面与待测透镜光学表面的曲面面形能够准确相符。     

Nanometer profile measurement of large aspheric optical surface by scanning deflectometry with rotatable devices: Uncertainty propagation analysis and experiments

High-accuracy mirrors and lenses with large dimensions are widely used in huge telescopes and other industrial fields. Interferometers are widely used to measure near flat surfaces and spherical optical surfaces because of their high accuracy and high efficiency. Scanning deflectometry is also used for measuring optical near flat surfaces with sub-nanometer uncertainty. However, for measuring an aspheric surface with a large departure from a perfect spherical surface, both of these methods are difficult to use. The key problem for scanning deflectometry is that high-accuracy autocollimators usually have a limited measuring range less than 1000″, so it cannot be used for measuring surfaces having a large slope. We have proposed a new method for measuring large aspheric surfaces with large slopes based on a scanning deflectometry method in which rotatable devices are used to enlarge the measuring range of the autocollimator. We also proposed a method to connect the angle data which is cut by the rotation of the rotatable devices. An analysis of uncertainty propagation in our proposed method was done. The result showed that when measuring a large aspheric surface with a diameter over 300 mm and a slope of 10 arc-deg, the uncertainty was less than 10 nm. For the verification of our proposed method, experimental devices were set up. A spherical optical mirror with a diameter of 35 mm and curvature radius of 5000 mm was measured. The measuring range of the autocollimator was successfully enlarged by our proposed method. Experimental results showed that the average standard deviation of 10 times measurement was about 20 nm.     

基于三维测量扫描线点云的表面重建

由结构光测量系统获得扫描线点云，通过剔除测量方向部分冗余数据点和插补扫描方向的稀疏数据，对物体表面原始三维数据密度进行适当调整。采用基于局部切平面簇的方法对调整后的数据点云进行表面重建，建立优化函数简化网格，并采用Loop细分法平滑网格，获得描述物体表面特征的重建表面。该方法解决了由扫描线点云重建物体表面的问题。     

A New Method of Non-Contact Measurement for Microtopography in Semiconductor Wafer Implementing a New Optical Probe Based on the Precision Defocus Measurement

In this paper, a new method of non-contact measurement has been developed for 3D topography for a semiconductor wafer, implementing a new optical probe based on precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. A distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. A precision calibration technique has been applied, giving about 10 nm resolution and 72 nm four-sigma uncertainty. In order to quantitise the micro pattern on the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and the excellent 3D measurement capability.     

透明台阶的白光干涉测量方法研究

Veeco NT3300表面轮廓仪是基于白光干涉原理的一种非接触测量设备,它的垂直扫描干涉模式可以实现对物体表面形貌的非接触测量。在利用垂直扫描干涉模式对光刻胶形成的透明台阶测量时,设置不同的测量参数会导致较大的测量误差,通过对垂直扫描干涉模式的原理和测量系统的分析,找到了误差产生的原因,并通过合理的测量参数的设置,实现了对透明台阶的准确测量,满足了应用需求。     

波长轮换与相移扫描相结合的表面形貌测量系统

用光学显微干涉法进行表面形貌测量时其深度测量范围的扩大和形貌测量精度的提高是一对矛盾。为此,本文设计出了一种基于波长轮换与相移扫描相结合的三波长表面形貌测量系统,并提出了一种基于椭圆拟合与相位差大小尺度相结合的相位提取与识别算法。将这种算法运用于多波长干涉图像的数据处理,有效地提高了形貌的整体测量精度,并拓展了深度测量范围。实验结果表明:在深度测量范围扩大近15倍的条件下,采用粗糙度国家基准校准的方波多刻线样板得到的表面粗糙度数据与校准数据的相对误差仅为4.12%,表明该系统在一定的深度范围内能够实现表面形貌的高精度测量。另外,针对该系统设计的多波长相位识别算法对环境噪声要求不高,可以支持系统的高噪声或在线测量。     

Embedded CMAC learning controller for scan-tracking measurement in copying manufacture: results of a case study

Surface scan-tracking measurement is one of the key technologies in copying manufacture. In conventional scan-tracking measuring processes of irregular surface, the model surface geometric shape and the friction between the probe and model surface are two main factors that can seriously affect the measuring accuracy and efficiency. In order to reduce the impact of these factors and improve measurement efficiency while maintaining measurement accuracy, this paper presents a novel embedded cerebellar modular articulation controller (CMAC) learning controller for scan-tracking measurement in copying manufacture. New approaches to model surface features (including geometric feature and friction feature) identification and quantification are given specifically. Conventional scan-tracking control law is improved by taking into account the impact of model surface feature, and it is combined with CMAC neural network so that it can automatically predict the surface features and adjust the scan-tracking velocity in advance. Thus, high measuring efficiency can be obtained by accelerating scan speed in smooth areas of model surface and decelerating prior to scanning the surface feature cusp regions. Working with a commercial open CNC system, the design steps, integration process, and results of applying the embedded CMAC learning controller were described in detail through the examples of real measurement. Actual industrial tests show a higher measurement efficiency which demonstrates the effectiveness of proposed control strategy for scan-tracking measurement.