Study on Laser Visual Measurement Method for Seamless Steel Pipe Straightness Error by Multiple Line- structured Laser Sensors

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ａｔｐｒｅｓｅｎｔ ,ｌａｒｇｅ ｓｃａｌｅｓｔｒａｉｇｈｔｎｅｓｓｅｒｒｏｒｍｅｔｒｏｌｏｇｙｉｓｔｈｅｃｏｎｃｅｒｎｏｆｔｈｅｗｏｒｌｄ ,ｆｏｒｅｘａｍｐｌｅ,ｔｈｅｍｅａｓｕｒｅｍｅｎｔｏｆｓｔｒａｉｇｈｔｎｅｓｓｅｒｒｏｒｏｆｏｖｅｒ ｔｅｎ ｍｅｔｅｒ ｌｏｎｇｓｅａｍｌｅｓｓｓｔｅｅｌｐｉｐｅ[1] .Ｗｉｔｈｒｅｇａｒｄｔｏｓｔｒａｉｇｈｔｎｅｓｓｍｅａｓｕｒｅｍｅｎｔｍｅｔｈｏｄ ,ｔｈｅｒｅａｒｅｍａｉｎｌｙｌａｓｅｒａｌｉｇｎｍｅｎｔ,ａｕｔｏ ａｌｉｇｎｍｅ…     

广义位移传感器在形状误差和误差运动分离中的读数贡献

详细推导并统一了形状误差和误差运动高精度检测 分离技术中各类传感器的读数方程 ,包括传统的差动变压器式位移传感器、电涡流式位移传感器、电容式微位移传感器和近年来出现的激光微位移传感器、激光角位移传感器以及后两者组合成的组合式广义位移传感器。以统一的列表方式阐明了各传感器的读数贡献。其优点是 :根据选用的误差分离方法和与之适配的传感器 ,便可按列表方式快速、方便地排出用于直线、圆、圆柱度和平面度等误差分离的原始读数方程 ,并对误差分离的可行性作出了初步分析     

激光投影成像式运动目标位姿测量与误差分析

为了实现室内运动目标位姿的高精度测量,建立了一套激光投影成像式位姿测量系统.该系统利用两两共线且交叉排列在同一平面上的点激光投射器作为合作目标捷联在运动目标上,通过与光斑接收幕墙的配合共同组成运动目标位姿测量基线放大系统,利用高速摄像机实时记录幕墙上投影光斑的位置,利用摄像机标定结果求解投影光斑的世界坐标,利用投影光斑之间构成的单位向量建立运动目标位姿解算模型.最后,根据测量原理推导了图像坐标提取、摄像机外部参数标定、光束直线度与目标位姿解算结果之间的误差传递函数.实验结果表明,当摄像机的视场范围为14 000mm×7 000mm时,测量系统的姿态角测量精度为1′(1δ),位置测量精度为5mm,且误差大小与目标位姿测量误差传递函数理论计算值一致,验证了本文提出的目标位姿测量方法与测量误差传递模型的准确性,能够满足目标位姿测量高精度的要求.     

Straightness Measurement Using Laser Diode and CCD Camera

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｍａｎｕｆａｃｔｕｒｅａｎｄａｓｅｍｂｌｅｏｆｍｏｄｅｒｎｍａｃｈｉｎｅｓａｎｄｉｎｓｔｒｕｍｅｎｔｓ，ａｎｉｎｄｉｓｐｅｎｓａｂｌｅｒｅｑｕｉｒｅｍｅｎｔｉｓｔｈｅｃｏｎｔｒｏｌｏｆｆｏｒｍａｎｄｐｏｓｉｔｉｏｎｅｒｏ...     

多程放大器光束空间分布的优化设计

This paper focuses on measuring straightness of large-scale dimension by using laser diode fiber alignment, diffraction imaging technique and a CCD camera. In this method, we use a laser diode fiber alignment beam as the datum reference of straightness, deviation of the measured from this datum, can be detected by a CCD camera directly. Also a novel image processing algorithm is presented. The experiment result shows that the measurement range of L (m), the measurement accuracy of the system is 3+2.3×10-6L(\mm).     

基于线结构光的视频内窥镜测量技术

针对视频内窥镜的测量需求，提出了一种基于线结构激光照射的测量技术。采用线激光作为定标光照射物体表面，建立了线结构光成像模型，标定了不同物距时的放大率和图像中线位置间的比例系数。通过构建测量平台计算了物体的几何参数，实验结果表明测量误差在10%以内，能够满足视频内窥镜观测和测量要求。     

A straightness measurement system using a single-mode fiber-coupled laser module

In this paper, a quite simple and novel straightness measurement system is proposed. The laser beam from a single-mode fiber-coupled laser module is highly stable, and can be used as the reference line for straightness measurements of any mechanical system. A corner retro-reflector is used as the moving target in the system in order to sense the straightness error and to reflect laser beam from measurement head back to it. In this way, there is no cable connection in the moving target, which is necessary for straightness measurements in workshop. At the same time, relationship between voltage output from a quadrant photodiode detector and its displacement was analyzed, and the theoretical analysis shows a good consistence with practical measurement results, which gives a way to enlarge the measurement range of the system. Comparative results of straightness measurement with a dual frequency laser interferometer were given, and repeatability with one micrometer at the distance of 1 m was gotten by the system.     

A Rapid Calibration Technique for Scanning Line-Structured Laser Sensor

A novel procedure to calibrate the scanning line-structured laser sensor is presented. A drone composed of two orthogonal planes is designed, with the result that camera parameters and light-plane equation parameters is achieved simultaneously.     

多自由度误差同时测量中的滚转角测量方法

提出了一种滚转角误差测量的新方法,该测量方法能够实现与其他自由度误差测量相集成,构成多自由度同时测量系统.系统采用带温控的半导体激光器单模光纤组件作为光源,有效降低了激光器本身的光线漂移,为测量提供高精度高稳定性的基准光线;采用特殊棱镜作为测量的敏感单元,通过此棱镜出射光线的直线度测量,间接实现滚转角误差测量.实验过程和数据表明,测量系统具有很好的稳定性和重复性,通过与电子水平仪的对比实验,验证了该方法的可行性,测量精度约为2".     

激光干涉测长未对准误差分析

分析了激光干涉测长原理,建立了测长光路中角锥棱镜的光线偏移模型及内部光程模型,推导了忽略直线度误差及角度误差的未对准误差对定位误差测量结果影响关系的简洁表达式,进行了定位误差的测定实验,给出了未对准误差的一种定量评估方法.     

Laser Vision Measurement System and Assessment Method for SMIC Lead Coplanarity

In this paper, a successful application of line-structured laser sensor, involved in SMIC chip lead coplanarity measurement, is presented. With the experimental measurement system and its corresponding mathematics model, a contact-datum-plane assessment of SMIC chip lead coplanarity is developed to provide method for on-line measurement.     

The laser reference line method and its comparison to a total station in an ATLAS like configuration

A new type of measuring system, the Laser Reference Line, is proposed as a metrological tool and can be used within limited space to ensure a precise installation along an axis on the ATLAS interaction point. A simplified ATLAS like beam pipe mock-up is used for this test. The coordinates of the beam pipe are measured three times using the new method and a Total Station. The measurements agree within the measurement error of the Total Station, which indicates that the precision of the laser reference line is suitable for this specific task in the ATLAS experiment.     

高速重轨平直度在线检测研究

重轨的平直度检测是重轨生产过程中重要的一个环节,该项检测的速度、准确性、稳定性等因素直接影响重轨总体质量。 本文以中国某大型钢铁集团轨梁厂的重轨平直度检测现状为背景,利用激光传感、数据采集、计算技术等现代技术,设计了一套基于并行计算的重轨平直度在线检测系统。系统采用14个激光位移传感器和2个旋转编码器分别对于重轨的7个水平方向位移测点、7个竖直方向位移测点、和重轨传输方向的位移进行实时测量,得到的信号转换为数字信号后,在PC机内通过GPU并行计算进行同步配准、块内数据分析、块间数据分析、帧间数据分析等处理,除去粗糙度、氧化铁皮、高频振动、低频振动等干扰,最后得到并输出平直度信息。实验及现场应用表明,该方法检测速度可达到3m/s、精确度可达到0.1mm.     

Effects of relative positioning of energy sources on weld integrity for hybrid laser arc welding

This study is concerned with the effects of laser and arc arrangement on weld integrity for the hybrid laser arc welding processes. Experiments were conducted for a high-strength steel using a 4 kW Nd: YAG laser and a metal active gas (MAG) welding facility under two configurations of arc–laser hybrid welding (ALHW) and laser–arc hybrid welding (LAHW). Metallographic analysis and mechanical testing were performed to evaluate the weld integrity in terms of weld bead geometry, microstructure and mechanical properties. The morphology of the weld bead cross-section was studied and the typical macrostructure of the weld beads appeared to be cone-shaped and cocktail cup-shaped under ALHW and LAHW configurations, respectively. The weld integrity attributes of microstructure, phase constituents and microhardness were analyzed for different weld regions. The tensile and impact tests were performed and fracture surface morphology was analyzed by scanning electron microscope. The study showed that ALHW produced joints with a better weld shape and a more uniform microstructure of lath martensite, while LAHW weld had a heterogeneous structure of lath martensite and austenite.     

Laser Alignment Techniques for Simultaneously Measuring Five Degree-of-freedom Deviations of the Object

An optical measurement system has been developed for the simultaneous detection for five degree-of-freedom (DOF) deviations of the object. The measuring system designed bases on laser holographic technique, laser alignment technique, laser drift compensation technique and magneto-optic modulating technique where a single laser beam is used as datum line. This measuring system is applied to multiple degree-of-freedom alignment and measurement of fine deviation, and it carries out the automatic testing in a deformation of machine tool, or the loaded axon in a strain wind tunnel balance. Through actual calibration and measurement, the resolution of the system is estimated to be 4 μm for linear displacement error measurement and better than 2″ for angular error measurement with a 1 m offset between laser and a photoelectric receiving target.     

Laser Alignment Techniques for Simultaneously Measuring Five Degree of freedom Deviations of the Object

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｌｉｇｎｍｅｎｔｏｆａｗｏｒｋｐｉｅｃｅｏｒｔｈｅｐｏｓｉｔｉｏｎａｎｄａｔｉｔｕｄｅｏｆａｎｏｂｊｅｃｔｉｎｓｐａｃｅａｌｗａｙｓｒｅｑｕｉｒｅｓｕｐｔｏｓｉｘｄｅｇｒｅｏｆｆｒｅｅｄｏｍｄｅｖｉａｔｉｏｎｓ,...     

Laser scattering with a rapidly tuned dye laser

A facility is described for the measurement of the total spectrum produced by laser radiation scattered from a plasma during one laser pulse. The dye laser is electrooptically tuned by a high frequency voltage applied to a modified Lyot filter within its cavity. The scattered spectrum is registrated together with the laser reference signal by a transient recorder and processed afterwards. Both measuring time and inaccuracy could be reduced drastically. Scattering experiments have been accomplished in a H₂ cascade of 5 mm diameter arc at atmospheric pressure, and at 14 and 20 A, respectively. For this arc very precise spectroscopic results are available for checking the accuracy of the scattering measurements. Both the spectroscopic line and continuum experiments yield a temperature which lies between electron and ion temperature if there is no local thermal equilibrium, whereas the pure electron temperature is provided by the scattered spectrum. The agreement between spectroscopic and scattering results within the high error limits is the experimental proof for the applicability of this new scattering technique which requires only about one hundredth of the measuring time, as compared with the usual shot-to-shot registration.     

激光跟踪仪检验非球面面形的方法

通过扩充激光跟踪仪的现有功能,提出了一种适用于非球面研磨和粗抛光阶段以及中低准确度非球面面形的快速检测方法.分析了测试原理,设计规划了检测流程.利用激光跟踪仪的靶标球对非球面表面进行多点接触测量,并将测量的结果与非球面CAD模型进行分析对比、处理和运算,获得非球面的面形分布信息.结合实例对一口径为420 mm×270 mm的离轴非球面进行了面形检测,并与零位补偿结果进行对比,结果表明,两种方法测试的面形误差分布是一致的,其峰谷值和均方根值的相对偏差分别仅为6.22%和3.37%.该方法无需其它辅助光学元件就能够准确地实现对大口径非球面面形的检测,测试数据处理和数学运算简单,实验操作简单易行.     

激光跟踪仪检验非球面面形的方法

通过扩充激光跟踪仪的现有功能,提出了一种适用于非球面研磨和粗抛光阶段以及中低准确度非球面面形的快速检测方法.分析了测试原理,设计规划了检测流程.利用激光跟踪仪的靶标球对非球面表面进行多点接触测量,并将测量的结果与非球面CAD模型进行分析对比、处理和运算,获得非球面的面形分布信息,结合实例对一口径为420 mm×270 mm的离轴非球面进行了面形检测,并与零位补偿结果进行对比,结果表明,两种方法测试的面形误差分布是一致的,其峰谷值和均方根值的相对偏差分别仅为6.22％和3.37％.该方法无需其它辅助光学元件就能够准确地实现对大口径非球面面形的检测,测试数据处理和数学运算简单,实验操作简单易行.     

Laser self-mixing interference fibre sensor

Fibre sensors exhibit a number of advantages over other sensors such as high sensitivity, electric insulation, corrosion resistance, interference rejection and so on. And laser self-mixing interference can accurately detect the phase difference of feedback light. In this paper, a novel laser self-mixing interference fibre sensor that combines the advantages of fibre sensors with those of laser self-mixing interference is presented. Experimental configurations are set up to study the relationship between laser power output and phase of laser feedback light when the fibre trembles or when the fibre is stretched or pressed. The theoretical analysis of pressure sensors based on laser self-mixing interference is indicated to accord with the experimental results.