图像测量技术在汽车工业中的应用

1引言 图像测量技术是将图像处理技术应用于测量领域的一种新测量方法.它将被测对象的图像作为信息的载体,从中提取有用的信息来达到测量目的.图像测量方法具有非接触、高速度、动态范围大、信息丰富等优点,受到国内外测量领域的重视.目前它已广泛应用于汽车外观检测、车身冲压件、发动机、变速箱机加件几何尺寸测量.     

图像测量技术在汽车工业中的应用

图像测量技术是将图像处理技术应用于测量领域的一种新的测量方法。它将被测对象的图像作为信息的载体，从中提取有用的信扈．来达到测量目的。图像测量方浩具有非接触、高速度、动态范围大、信息丰富等优点．受到国内外测量领域的重视。目前它已广泛应用干汽车外观检测、车身冲压件。发动机、变速器切削加工零件几何尺寸测量。     

复杂零件精密尺寸测量方法的研究进展

随着各类机械零件集成化程度不断提高,其结构也越来越复杂,传统的测量技术已无法实现对现代复杂构造零件尺寸的精密测量.近年来出现的结构光三维测量、激光扫描测量等先进的测量技术克服了传统测量方法的不足,提高了尺寸测量效率和精度.归纳了结构光三维测量技术、机器视觉测量技术、蓝光扫描测量技术、激光三角法测量技术、工业CT尺寸测量技术的测量原理及研究进展,并对几种测量技术的优缺点和精度进行了对比分析.     

超精密测量技术的动向

<正> 1、对超精密测量技术的期望作为提高产品质量和新技术开发的基础技术之一,突破现在测量极限的超精密测量技术的开发是不可缺少的。很多场合已期待有μm级至nm级领域的测量技术的出现。如激光盘的纹道是典型的亚微米测量领域,它要求能够对宽小于几个微米,深0.1微米的纹道尺寸、形状进行测量。     

产品推荐

瓦尔特(无锡)有限公司HEVLICHECK高精度测量机Waller公司的Helicheck测量机,在当今多样的测量技术领域里铺设了一个全新的测量标准。带有4个NC轴和3个CCD照相机的测量机可以采用非接触式的测量方式,实现刀具一次装夹后对周齿、切削刃和端面的几何尺寸以及跳动等参数进行全自动测量。     

基于机器视觉的微电极自动测量技术北大核心

基于数字图像处理技术和MATLAB软件设计了微电极自动测量系统。对采集到的电极图片进行图像预处理、图像分割及尺寸测量。测量用电化学腐蚀制备的微电极,结果表明系统可以测量圆柱型与球头型两种电极的直径尺寸以及同轴度误差,系统测量尺寸值与显微镜下人工检测的尺寸值相对误差在4%以内,表明该系统有测量精度高、检测速度快等特点,能够满足微电极尺寸测量的要求。     

基于机器视觉的微电极自动测量技术

基于数字图像处理技术和MATLAB软件设计了微电极自动测量系统。对采集到的电极图片进行图像预处理、图像分割及尺寸测量。测量用电化学腐蚀制备的微电极,结果表明系统可以测量圆柱型与球头型两种电极的直径尺寸以及同轴度误差,系统测量尺寸值与显微镜下人工检测的尺寸值相对误差在4%以内,表明该系统有测量精度高、检测速度快等特点,能够满足微电极尺寸测量的要求。     

组合式超大尺寸测量技术在EAST装置中的应用

组合式测量技术是精密测试技术的研究发展方向之一,激光跟踪仪和柔性关节坐标测量臂都是便携式高精度三维测量系统,通过坐标转换等技术,把这两种仪器组合在一起,可实现对超大尺寸、隐藏点的高精度测量。根据EAST核聚变装置现阶段的实际情况,把这种组合式超大尺寸测量方法应用到EAST的装配定位测量过程中。利用该方法对装置进行初步实验测量,结果表明这种方法可以解决EAST核聚变装置装配过程中的复杂测量问题,能为解决如航天器、舰船、加速器等其它大型装置的精密测量问题提供借鉴。     

工业测量技术在大尺寸、高精度定位工装中的应用

随着电子和计算机技术的发展,工业测量技术也得到了长足的发展。工业测量仪器也越来越多样化和人性化,其应用已经遍布科研、制造和安装等领域以及航天和电子等行业。工业测量以其高精度、广范围、迅捷处理能力,得到了广泛的认可和应用。在一大型射电望远镜天线安装工程中,需要1组大尺寸、高精度进行装配的定位,此工装用传统的机械加工和测量定位方法无法实现,而使用工业测量的仪器和方法来完成工装的定位工作,保证其精度满足使用要求。     

在线测量技术应用于白车身的生产尺寸监控

在线测量技术是白车身尺寸监控的重要手段。通过对白车身焊装尺寸测量技术的特点的分析,针对一汽-大众轿车二厂焊装车间质量管理中白车身的尺寸控制问题,结合在白车身生产现场的研究,提出了白车身生产中在线测量技术的优化方案。     

A new 2D error separation technique for performance tests of CNC machine tools

The error separation technique is widely adopted for many machine tool performance tests. The most common applications include roughness measurement, straightness measurement and spindle measurement. In this paper, two error-separation technologies, the straightness reversal technique and the semi-reversal technique, are developed. The straightness reversal technique can be adopted for the straightness measurement of a linear axis. The semi-reversal technique can be adopted for setting error separation in a contouring test and in the spindle error measurement. In this paper, mathematical models have been developed. In order to verify the possibility of the semi-reversal technique, related experimental work has been carried out.     

High accuracy plasma density measurement using hybrid Langmuir probe and microwave interferometer method

High spatial resolution plasma density measurements have been taken as part of an investigation into magnetic nozzle physics at the NASA/MSFC Propulsion Research Center. These measurements utilized a Langmuir triple probe scanned across the measurement chord of either of two stationary rf interferometers. By normalizing the scanned profile to the microwave interferometer line-integrated density measurement for each electrostatic probe measurement, the effect of shot-to-shot variation of the line-integrated density can be removed. In addition, by summing the voltage readings at each radial position in a transverse scan, the line density can be reconstituted, allowing the absolute density to be determined, assuming that the shape of the profile is constant from shot to shot. The spatial and temporal resolutions of this measurement technique depend on the resolutions of the scanned electrostatic probe and the interferometer. The measurement accuracy is 9%-15%, which is on the order of the accuracy of the rf interferometer. The measurement technique was compared directly with both scanning rf interferometer and standard Langmuir probe theory. The hybrid technique compares favorably with the scanning rf interferometer, and appears more accurate than probe theory alone. Additionally, our measurement technique is generally applicable even for nonaxisymmetric plasmas.     

An AFM scanning moiré technique for the inspection of surface deformations

An atomic force microscope (AFM) scanning moiré technique has been developed and verified in preparation for the measurement of deformations of single point diamond-turned surfaces. It is a non-destructive measurement method without introducing external reference and specimen gratings. This technique has also been successfully applied to measure thermal deformations of electronics packages without introducing an external reference grating. The principle of the formation of an AFM scanning moiré and strain measurement using this technique is explained in detail. Several important issues in its applications such as the measuring errors, scanning directions and selection of the number of scan lines are also discussed.     

A sub-nanometre spindle error motion separation technique

This work designs and validates a spindle error motion separation technique having a sub-nanometre measurement uncertainty. This technique overcomes typical measurement error sources arising from sensor, indexing or the repositioning of the artifact. We compare and assess various known reversal and multiprobe techniques by means of a novel error analysis method. From this, we develop an improved implementation of the multiprobe technique, which by-passes accurate indexing of the artifact and sensor(s) during testing, as well as unequal sensor sensitivities, in case multiple sensors are used. This is achieved by measuring the error motion consecutively under three different orientations by rotating the stator of the spindle utilising a high-precision indexing table. These modifications result in a measurement uncertainty that is four times smaller than the conventional multiprobe technique. Furthermore, the suppression of the low-order harmonics is reduced by an optimisation of measurement angles. Finally, several experimental tests are performed to quantify the measurement uncertainty and the influence of the measurement angles on the error separation. Repeatability tests on the radial error motion of an aerostatic rotary table show a measurement uncertainty of 0.455 nm.     

Design and Implementation of a Technique for Iterative Magnetorheological Jet Polishing

This article introduces a technique for iterative high precision freeform lens polishing, with operations alternating between a fabrication and a measurement unit. The technique is implemented using a Magnetorheological Jet Polishing (MJP) machine as fabrication unit, and a sub-aperture stitching interferometric system as measurement unit. The two units are separately located and have different internal coordinate references. Precision integration of the two is the key to realize high performance iterative polishing. In our study, application of the proposed technique yields a peak to valley (PV) value of 1/7λ in polishing flat optical elements.     

Luminescent Molecular Sensors for Assessment of Temperature Field in Machining

A new technique based on luminescent molecular sensors is utilized in these series of experiments for measurement of temperatures in material removal processes. 2-Dimensional machining of metals at low speeds and surface grinding configurations are used as the model experimental systems to understand the efficacy of this experimental technique. The experiments were conducted with a series of luminescent sensors and binder combinations for the temperature measurement. The luminescence of the sensor was measured through a charge-coupled device imaging camera, and intensive calibration exercises were performed on these sensors. Excellent agreement in the temperature fields measured through this new experimental approach and traditional infrared thermography is seen here. This technique offers the unique capability of allowing measurement of temperatures in the presence of a lubricant, akin to manufacturing conditions in situ. Extension of the technique to measure the temperature field at the tool-chip contact is described.     

基于面阵传感技术的圆柱度测量新方法

针对现行圆柱度测量方法的局限性和存在的问题,提出一种基于面阵传感技术的圆柱度测量新方法———多孔径重叠扫描拼接测量。该方法以数字光栅条纹投射技术为单视角测量手段,利用多孔径重叠扫描拼接技术实现各个单视角面形数据的精确融合拼接,从而获得零件的整个圆柱表面的面阵数据。文中给出圆柱度扫描拼接测量原理、拼接模型及算法,并通过对样品轴实测证明该方法的准确性和可行性。该方法具有非接触、高效、全场的特点,且能够满足新一代GPS(geometrical product specifications,产品几何技术规范)标准的采样要求,从而为圆柱度的精确评定提供可靠的数据信息。     

The measurement setup for real-time biomechanical analysis of rowing on an ergometer

This paper presents the development and evaluation of the measurement setup for a real-time biomechanical analysis of rowing on an ergometer. The setup consists of a measurement system and a system for data processing. The measurement system consists of a Concept2 rowing ergometer instrumented by force sensors, incremental encoders and an optical system for measuring the kinematics. The measurement data is used as an input to a dynamic model which calculates the rower’s body joint loadings. Real-time data processing and analysis provide real-time feedback on rowing performance and technique to the user. For the evaluation of assessment methodology, five top-level rowers and five non-experts newly introduced to rowing participated in an evaluation experiment. The noticeable distinctions between the measured parameters in the experts and non-experts were measured. The results show that this measurement setup can be successfully used for detailed characterization of rowing technique.     

A travelling photothermal technique employing pyroelectric detection to measure thermal diffusivity of films and coatings

A travelling thermal wave technique employing optical excitation and pyroelectric detection of thermal waves propagating along a material film/coating on a substrate is described. The method enables direct measurement of thermal diffusivity. The technique involves measurement of the phase lag undergone by an optically excited thermal wave as it propagates along the coating. The set up has been automated for convenient and fast data acquisition and analysis. The technique has been adapted to measurement of thermal diffusivity of a commercial paint sample coated on glass and copper substrates. It is found that thermal diffusivity of the coating is independent of the thermal conductivity of the substrate. Dependence of thermal diffusivity on coating thickness shows exponential increase, with value reaching a constant at a characteristic high thickness. Measurements have been carried out on a few other samples with wide variations in thermal diffusivity, and the results compared with available reports or results obtained following other techniques. Analyses of the results show that the technique allows measurement of thermal diffusivity of coatings and films with uncertainties better than ±2.5%.     

Characterization of thermoelectric elements and devices by impedance spectroscopy

This article describes a new measurement technique that utilizes impedance spectroscopy for the characterization of thermoelectric materials and devices. Two circuit models were developed and used to help explain the impedance spectroscopy data using transmission line theory and a coupled electrothermal model. Two testing configurations have been investigated including one based on a sinusoidal source (ac lock-in technique) and one based on a pulsed wave source. Methods for reducing the measurement times for this technique are discussed. In addition, the influence of radiation losses on this measurement technique has also been analyzed to further understand the limitations of this technique at higher temperatures.