A Portable Noncontact Profile Scanning System for Aircraft Assembly

Three-dimensional(3D)profile scanning plays a crucial role in the inspection of assembled large aircraft.In this paper,to achieve noncontact automatic measurements of the high-reflective profiles of large-scale curved parts and components,an automated noncontact system and method with high accuracy and high efficiency are presented.First,a hybrid 3D coordinate measurement system based on proximity sensors and cameras is proposed to obtain noncontact measurements while avoiding the influence of high reflection on the measurement accuracy.A hybrid measurement model that combines the one-dimensional distances measured by the proximity sensors and the 3D information obtained by cameras is proposed to determine high-accuracy 3D coordinates of the measured points.Then,a profile-driven 3D automated scanning method and strategy are designed to rapidly scan and reconstruct the profile within the effective range without scratching the profile or exceeding the measurement range of the proposed system.Finally,experiments and accuracy analyses are performed in situ on an assembled tailplane panel(approximately 1760 mm×460 mm).The automated scanning process is completed in a timeframe of 208s with an average error of less than 0.121 mm for profile reconstruction.Therefore,the proposed method is promising considering both the high accuracy and high efficiency requirements of profile inspections for large aircraft.

Development of laser and microwave scanning technologies in the blast furnace burden profile and lining condition measurement at CSC

In order to stabilise the operation of the blast furnace and to raise its operation efficiency,research works for the application of microwave and laser scanning technologies to the measurement have been intensively carried out at China Steel Corporation(CSC).To monitor the burden profile during the operation,a microwave burden profile measuring system was developed.The system consists of a radar unit,a signal processing system, and a driving device which is capable of rotating the radar to scan the burden surface in a specified direction.A nitrogen cooling system was designed to protect the measurement system.A prototype burden profile meter was successfully tested in No.1 blast furnace in 2008,and a permanent one was installed at No.3 blast furnace.The system has provided useful information for adjusting the charging sequence in No.3 blast furnace.For another application,3 - D laser scanning technology is employed to monitor the blast furnace lining condition.To this end,a data registration method has been developed,through which two measured range images sensed at different period and locations can be fitted into the same coordinate system.In practice,the erosion of the blast furnace lining can be estimated when the current inner profile is compared with that taken before the blow-in operation. This technology is also adopted to evaluate the performance of gunning operation in the blast furnaces at CSC.

多杆仿形式茶枝柑剥皮取肉装置设计与试验

广东新会一带的茶枝柑是“南药”广陈皮唯一来源,其初加工过程中剥皮取肉环节自动化程度低、并容易产生“汁溅”导致腐蚀广陈皮(俗称“烧皮”),为了实现茶枝柑初加工全程自动化,该研究研发一种新型茶枝柑自动剥皮取肉装置以解决上述问题。首先采用3D扫描与重构技术,获得人手剥皮时果皮真实轨迹和姿态数据,建立人手剥皮位姿数学模型;然后以人手剥皮位姿信息为目标,设计多杆仿形机构并使其轨迹和姿态逼近人手剥皮位姿;最后对设计好的多杆仿形机构进行仿真验证和分析,并加工装配出样机进行实际剥皮试验。试验结果表明,该装置可较好模拟人手剥皮时的位姿曲线,配合真空吸盘吸附,可实现茶枝柑机械式自动剥皮,然后配合包络式柔顺机械爪,实现了茶枝柑无损剥皮取肉,试验结果显示剥皮无损率为80%。该研究结果可为柑橘类水果剥皮初加工提供了理论和试验参考。

基于多视数据重构损失标定的叶片型面光学检测

航发叶片型面检测是保证叶片加工质量、工作性能和使用寿命的关键环节。对此,该文开发一套基于线激光器的叶片型面检测平台;在完成线激光器与叶片相对位姿校准及Z向测量基准建立基础上,实现叶片型面特定截面处型线数据的多视采集;提出一种基于多视数据重构损失标定回转中心的型线重构方法。以两种典型燃气轮机导向叶片为检测对象,所提出方法获取的检测数据与三坐标测量机检测数据的对比结果表明,轮廓度检测平均绝对偏差在0.022 mm以内,最大标准偏差为0.0186 mm,最大RMS估计为0.0251 mm;特征参数检测最大偏差为0.0401mm。实验结果验证了所提出方法面向叶片型面检测的可行性。

基于三维点云的轮对踏面轮廓动态测量教学实验设计

通过MV-DP090-02B激光轮廓传感器获取轨道车辆轮对踏面轮廓影像信息,再将物体表面轮廓位置转化为三维点云数据,并对数据进行降噪和特征提取,然后对踏面轮廓进行三维重建。文章结合轮对踏面动态测量实验,对轮对低速转动过程中的踏面轮廓进行了扫描。数据处理结果表明,基于MV-DP090-02B激光轮廓传感器获取的三维扫描点云数据及相关数据处理,可以动态测量轮对转动过程中的踏面轮廓;MV-DP090-02B激光轮廓传感器能够满足实验室的测量需求,操作简便,是“轨道交通车辆机械检修”课程实验中轮对踏面轮廓获取的一种新方法。

一种基于5G应用的圆极化微带相控阵天线

本文提出一款应用于5G频段,可实现方位面±40°波束扫描的圆极化微带相控阵天线。该相控阵天线单元是由矩形贴片、上下介质板、缝隙耦合馈电结构、金属反射板构成。利用切比雪夫综合法的一分八不等分功分器实现相控阵天线的馈电形式。测试结果表明,阵列天线的驻波比带宽为3.25 GHz~3.69 GHz,端口隔离度大于25 dB,扫描过程中增益最大为21 dB,增益衰落小于3 dB,最大扫描角处轴比为2.89 dB。该天线具有低剖面、高隔离度、高增益以及良好的波束扫描性能等优点。

动车侧墙板轮廓扫描装置及性能分析

动车组侧墙板是铁路车辆的关键组成部件,通常由高强度合金材料制成,受焊接和成型工艺影响,动车侧墙板与理论模型存在偏差。因此,当动车组侧墙板制成后,进行严格的质量检测是至关重要的。为了将腻子喷涂机应用于侧墙板制造过程中,改善侧墙板喷涂过后表面的平整度,设计了一种动车组侧墙板轮廓扫描装置。基于先进的激光测量技术,结合高精度的传感器与数据处理系统,能够快速准确地获取侧墙板表面的三维轮廓信息。相对于传统的测量装置,不受复杂曲面形态的限制。由于扫描装置在运行中不可避免地会产生振动,对数据采集过程会产生影响,利用加速度传感器,获取装置在扫描运行过程中的振动数据。通过对振动数据的分析,确定装置的主要振动模式,并进一步优化了相机的布局,较大程度降低了振动对数据采集产生的影响。

一种低剖面宽带宽角扫描圆极化阵列天线设计

提出一种单馈点旋转偶极子圆极化天线,通过弯曲支撑金属板和优化其位置实现了低剖面单元天线设计(0.09个波长,中心频点)。利用紧凑型结构形式,保证结构强度并兼顾轻量化,比传统的低剖面微带天线重量更轻、口径更小、馈电网络更简单。采用两级子阵旋转组阵方式,实现±53°阵列扫描,轴比优于4 dB。仿真与测试结果对比分析表明,该天线具备良好的设计一致性,可为圆极化宽角扫描的需求领域提供潜在应用。

Acoustical imaging of the nearshore seafloor depositions and deformations,a key study for Western Istanbul,Türkiye

To protect the sustainability of the benefits from seas and near coastal areas,which have under the effect of the very complex hydrodynamic conditions and intensive human activities,without disrupting the balance of nature,it is necessary to image the status of the seafloor features.Therefore,this study presents the deformations,depositional conditions,underwater constructions,and the other non-natural impacts on the seafloor of the nearshore area at western Istanbul(between Küçükçekmece and Büyükçekmece lagoons)where it intensely used by the citizens.The results of the study may provide some guidance for understanding the impacts and risk factors of uses that are or will be conducted in coastal and/or near-coastal areas.Construction planning for civil coastal structures and areas should be done in great harmony with nature,minimizing negative environmental impacts.Although sediment distribution in the area is generally quite complex,the current state of the region,wave action,hydrodynamic conditions,the amount of material transported from the land,and bathymetry are important influencing factors.The seafloor has been damaged primarily by anchor deformation and associated bottom scanning,as well as disturbing trawl tracks.The seafloor was observed as partially shallowing near the constructions(such as natural gas pipelines,fishermen’s shelter,and port piles)of coastal areas and associated with sand deposits.Therefore,scanning the seafloor using side-scan sonar may provide valuable frequency data to prevent future disruptions.

选区激光熔化圆孔结构的有限元模拟及实验验证

圆孔是选区激光成型件中常见的结构,但实验难以对该成形过程中的变形行为进行评估,而有限元(FE)模拟技术已经广泛用来预测选区激光熔化(SLM)成形过程中的变形行为。因此,本文采用FE方法表征SLM过程中GH4169圆孔模型尺寸精度并用实验验证FE结果。在此基础上建立了多层多道次的有限元模型用于研究激光功率、扫描速度和扫描策略及基板预热对通过SLM构建的GH4169圆孔结构制件成形的影响。研究结果表明:随着激光功率的上升和扫描速度的增加,圆孔的尺寸精度是先上升后下降,最佳的工艺参数是激光功率为300 W,扫描速度为1200 mm/s,且模拟结果与实验结果能够较好地吻合。此外,模拟结果还表明在67°旋转轮廓扫描下可以得到更高的尺寸精度,而基板是否预热对圆孔成形的尺寸精度影响不大。因此,本文的研究可以为圆孔结构制件SLM工艺提供优化指导。

Ku频段低剖面宽角扫描阵列天线设计

基于当前无线通信技术对于低剖面天线的强烈需求,提出并设计了一种应用于Ku频段的低剖面宽角扫描阵列天线。该天线阵列单元的整体尺寸很小,仅有8 mm×8 mm×10 mm,剖面高度10 mm,具有低剖面特性。该天线通过采用交指型紧耦合偶极子结构缩小了单元间距并且拓展了带宽,采用开口型电阻方环以及顶部介质覆盖层提高了宽角扫描能力。仿真结果表明,该天线在11~17 GHz工作频段内VSWR<2,E面70°角扫描VSWR<2.8,H面40°角扫描VSWR<2.6,20×20阵列最大增益超过20 dB。因此,该天线可以较好地应用于Ku频段的卫星通信以及机载雷达测量,并且剖面较低便于共形。

3D激光扫描技术在曲面建筑平立剖面图测绘中的应用

为了实现曲面建筑平立剖面图的精准测绘,将3D激光扫描技术应用到曲面建筑平立剖面图测绘工作中,实现测绘方法的优化。应用3D激光扫描技术获取曲面建筑点云数据,通过融合、去噪与过滤等步骤,实现对初始点云数据的预处理。提取曲面建筑轮廓线,经过曲面建筑结构数据测量和曲面建筑平立剖面图绘制两个步骤,输出曲面建筑平立剖面图的测绘结果。通过应用效果测试实验得出结论:通过3D激光扫描技术的应用,曲面建筑几何参数的测量误差明显降低,绘制的平立剖面图与实际曲面建筑结构之间的相似度更高,即3D激光扫描技术在曲面建筑平立剖面图测绘中具有良好的应用价值。

小圆柱圆度误差的线性扫描拼接方法研究

提出了一种替代传统旋转扫描法的小型圆柱体圆度测量新方法,即线性扫描拼接法。该方法采用表面轮廓仪将固定于专用工装上的小圆柱在不同的角度位置进行线性扫描,采取径向及圆周方向拼接成一系列圆弧轮廓,不需要将圆柱体与旋转基准对准,便实现小/微圆柱体的圆度测量。阐述了新方法的原理,基于新方法构建了圆度测量机,进行试验和不确定度分析验证了该方法的有效性,并使用传统圆度测量仪对试验结果进行了比较。

三种探测技术在舟山港航道扩建工程海底管线探测中的联合应用

海底管线路由探测对航道疏浚施工具有重要意义,而传统的探测技术手段单一,效率较低,无法确定掩埋段信息。为提高海底管线探测结果精度及作业效率,依托宁波舟山港条帚门航道扩建工程项目,综合利用侧扫声呐、浅剖及海洋磁探对工程区域海底管线进行探测:利用侧扫声呐成果作为裸露段海底管线探测结果的基本支撑,浅剖埋深结果与磁探反演埋深结果相互印证,共同提高了海底管线判别的准确性。工程应用结果表明,三种探测技术手段在海底管线探测方面的联合应用成果可靠,探测精度和作业效率显著提升,且具有较好的适用性,在类似项目中具有较好的参考和推广作用。

海上风电场地理信息综合服务关键技术

海上风电作为清洁能源,进行大力开发建设。地理信息在海上风电场建设运维、船舶航行安全方面发挥重要作用,也是海事通航尺度核定测量重要内容。海上风电场地理信息综合服务包含侧扫声呐探测、浅地层剖面探测、多波束水深测量及二三维一体化展示等关键技术。本文以粤东某风电场为例,进行了沉船扫海测量、风机基底探测、礁石浅点探测、电缆数据采集及风电场海域相关要素二三维一体化展示。结果表明,风电场地理信息数据需要结合浅地层剖面仪、侧扫声呐和多波束影像综合分析,提高数据的互补性和可靠性;基于潮汐模型与余水位监控法、海量多波束处理CUBE算法具有应用价值,磁法测量、下潜探摸和水下摄像判读可获取沉船更详细的信息。

三维激光扫描技术在古建筑平立剖图测绘中的应用

古建筑是文化和历史的见证,是精神文明的传承,测绘古建筑平立剖图是古建筑保护的重要工作内容。本文借助三维激光扫描技术优势,结合生产项目实例,介绍了基于Focus三维激光扫描仪的古建筑平立剖图测绘技术流程,并对古建筑平立剖图测绘成果进行精度分析与评定,为后续类似项目提供借鉴。

一种自由曲面三维形貌光扫描测量装置

工件表面形貌通常会对使用性能造成直接影响。由于目前常采用接触式测量,易受被测件材质及表面特性的影响。因此,为有效解决传统接触式测量仪面临的技术难题,本文研究了一种自由曲面三维形貌光扫描测量装置。

Experimental Investigation of Laser Surface Hardening of AISI 4340 Steel Using Different Laser Scanning Patterns

Laser surface transformation hardening becomes one of the most modern processes used to improve fatigue and wear properties of steel surfaces. In this process, the material properties and the heating parameters are the factors that present the most significant effects on the hardened surface attributes. The control of these factors using predictive modeling approaches to achieve desired surface properties leads to conclusive results. However, when the dimensions of the surface to be treated are larger than the cross-section of the laser beam, various laser-scanning patterns are involved. This paper presents an experimental investigation of laser surface hardening of AISI 4340 steel using different laser scanning patterns. This investigation is based on a structured experimental design using the Taguchi method and improved statistical analysis tools. Experiments are carried out using a 3 kW Nd: YAG laser source in order to evaluate the effects of the heating parameters and patterns design parameters on the physical and geometrical characteristics of the hardened surface. Laser power, scanning speed and scanning patterns (linear, sinusoidal, triangular and trochoid) are the factors used to evaluate the hardened depth and the hardened width variations and to identify the possible relationship between these factors and the hardened zone attributes. Various statistical tools such as ANOVA, correlations analysis and response surfaces are applied in order to examine the effects of the experimental factors on the hardened surface characteristics. The results reveal that the scanning patterns do not modify the nature of the laser parameters’ effects on the hardened depth and the hardened width. But they can accentuate or reduce these effects depending on the type of the considered pattern. The results show also that the sinusoidal and the triangular patterns are relevant when a maximum hardened width with an acceptable hardened depth is desired.

Oil Production Optimization by Means of a Combined“Plugging,Profile Control,and Flooding”Treatment:Analysis of Results Obtained Using Computer Tomography and Nuclear Magnetic Resonance

Due to long-term water injection,often oilfields enter the so-called medium and high water cut stage,and it is difficult to achieve good oil recovery and water reduction through standard methods(single profile control and flooding measures).Therefore,in this study,a novel method based on“plugging,profile control,and flooding”being implemented at the same time is proposed.To assess the performances of this approach,physical simulations,computer tomography,and nuclear magnetic resonance are used.The results show that the combination of a gel plugging agent,a polymer microsphere flooding agent,and a high-efficiency oil displacement agent leads to better results in terms of oil recovery with respect to the situation in which these approaches are used separately(the oil recovery is increased by 15.37%).Computer tomography scan results show that with the combined approach,a larger sweep volume and higher oil washing efficiency are obtained.The remaining oil in the cluster form can be recovered in the middle and low permeability layer,increasing the proportion of the columnar and blind end states of the oil.The nuclear magnetic resonance test results show that the combined“plugging,profile control,and flooding”treatment can also be used to control more effectively the dominant channels of the high permeability layer and further expand the recovery degree of the remaining oil in the pores of different sizes in the middle and low permeability layers.However,for the low permeability layer(permeability difference of 20),the benefits in terms of oil recovery are limited.

一种电磁耦合馈电宽带宽角扫描微带天线阵列

文中提出一种可实现宽频带大角度波束扫描的低剖面相控阵微带贴片天线。为实现宽带特性,该阵列天线采用了缝隙电磁耦合馈电和双层贴片的设计。由于介质基板的堆叠,微带贴片阵列在高频大角度扫描时往往会受到表面波的影响,从而引发高次模谐振并带来扫描盲区。针对这一现象,通过对堆叠的介质基板开槽抑制表面波传播,从而改善高频的阻抗匹配特性。此外,还在贴片两侧加载寄生条带以优化低频阻抗匹配,拓展带宽并保持低剖面外形。该天线剖面高度仅4.6 mm,约为高频波长的0.19倍,可满足许多低剖面载体平台的应用需求。仿真结果显示,该天线在±45°扫描和±60°扫描时可分别实现57.9%(有源驻波比≤2.25)和44.4%(有源驻波比≤2.75)的相对带宽。基于该设计加工了一款8×8阵列样机。阵列样机的驻波及方向图测试结果与8×8阵列的全波仿真结果吻合良好,有效验证了该微带贴片天线阵列的宽带和宽角扫描特性。