船舱流水孔自动识别跟踪焊接系统

船舶制造中,为加强船体强度,船舱底部设置许多格子间,其工作环境狭小且存在不连续焊缝,影响焊接生产效率. 现有焊接机器人无法识别流水孔特征点位置,目前主要由人工来完成焊接. 在旋转电弧传感焊接机器人的基础上,增加激光视觉传感器用于识别流水孔的特征点,结合嵌入式工控机和其它硬件,通过自主开发的VC++软件完成对船舱流水孔焊缝自动识别、跟踪及焊接. 结果表明,该系统便携灵活,适用于船舱格子间焊接作业且识别和跟踪效果良好.     

狭小空间直角角焊缝识别跟踪焊接系统

船舶制造中,为加强船体强度,船舱底部设置许多空间狭小的格子间,该类构件无法利用单一的传感方式进行自动跟踪焊接.介绍了直角角焊缝焊接机器人的硬件结构和工作原理,利用旋转电弧和激光视觉传感器相结合对焊缝信息进行采集.对直角转弯过程进行了运动学分析,对十字滑块和机器人本体的运动进行了规划,通过规划和实时控制相结合的方式进行焊缝跟踪.利用开发的移动机器人硬件系统,通过自主开发的VC++图像处理和控制软件进行焊缝跟踪试验.结果表明,该系统便携灵活适用于狭小空间直角角焊缝跟踪焊接作业,且识别和跟踪效果良好.     

基于视觉的工业机器人自动焊接引导研究

通过构建视觉空间坐标进行视觉图像坐标系的转换,实现了视觉像素点在图像坐标系的重构,并对图像目标点在不同视觉空间中进行标定。研究了使图像增强的方法,并在此基础上对视觉图像进行了焊缝边缘检测、特征提取与匹配,实现了焊件图像有效数据的输出。对有效视觉数据进行提取,并驱动工业机器人及外围部件引导焊枪沿目标路径或目标焊件运动,从而实现了焊接视觉引导的自动化。     

一种线激光V形焊缝中心点识别的改进算法

在机器人自动化焊接过程中,准确识别、提取出焊缝位置,对于焊接的精度与质量有着很大的影响。基于线激光的V形焊缝轮廓识别算法,在进行阈值分割时,有时由于线激光与V形焊缝接触时会产生激光的变形,导致局部光强下降,部分轮廓会消失。提出一种改进算法,首先通过双边滤波方法,达到图像平滑的目的;然后通过Canny边缘检测算法,准确地提取出线激光在焊缝上变形的区域;通过膨胀算法处理后,再去除焊缝轮廓留下的干扰直线;再通过直线细化算法,识别出与线激光相交的焊缝边缘轮廓点与中心点。最后识别出焊缝中心点位置。     

基于激光视觉传感的焊缝三维测量

焊缝的三维测量是焊接过程自动化领域的关键技术之一.为了能够还原焊缝表面的轮廓并计算其各项参数,本文提出了一种基于激光视觉的焊缝表面非接触式测量系统,重点介绍了光学成像系统的设计、检测系统参数标定方法以及结构光光条图像的处理过程,最终得到了较为理想的焊缝轮廓曲线,并结合标定结果对焊缝的参数进行了计算.实验证明,整个检测系统具有较高的检测精度和稳定性.     

基于极线约束与激光标识的空间焊缝的立体视觉检测

针对安装在焊接机器人末端的双目立体视觉系统,建立了左右图像坐标的极线约束方程.采用极线约束和激光标识相结合的立体视觉匹配方法,完成了相交圆管马鞍形空间焊缝的立体视觉检测.结果表明,含激光条纹的焊缝图像,经细化、去毛刺处理后,可以得到分段光滑的曲线,通过曲线奇变点检测与曲线—极线相交点检测两种方法的融合,实现了空间焊缝检测点在左右图像中的可靠匹配,从而提高了焊缝及周边结构立体视觉检测的准确性.对检测的马鞍形焊缝及周边圆管的三维数据进行了重建,与实际结构尺寸比较误差小,满足一般机器人自动焊接过程中的焊缝检测要求.     

弧焊机器人中焊缝的识别处理

图像的处理与识别在焊接机器人的视觉系统中起着关键的作用,在本试验中通过摄像头拍摄焊缝,获取原始图像,然后通过图像采集卡将拍摄的图片采集到计算机内部,对原始图进行灰度处理、滤波、阈值处理,提取出焊缝的初始轮廓,由计算系统进行处理,提取出轮廓特征,然后转换为计算机容易识别的数据,机器人焊接系统根据这些有用数据对目标对象进行控制、监测或其他操作,以实现焊接生产智能化、提高焊缝质量和焊接生产率.提供给弧焊机器人的视觉处理系统的这些数据,可以提高弧焊机器人的焊接精度,实现自动纠偏,并对焊接系统提供可靠的数据.     

基于视觉传感器的焊缝图像识别与跟踪控制技术研究

针对传统"示教法"机器人焊接效率低、精度不高的问题,基于视觉传感技术对焊缝图像识别与跟踪技术进行研究。利用中值滤波和阈值分割的方法对图像进行预处理,并采用动态ROI提取与最小二乘法相结合的方法提取焊缝特征点,以解决弧光、飞溅等因素对图像的影响。同时,设计了激光焊缝跟踪系统,并将焊枪姿态作为指标对对焊缝的跟踪效果进行了实验分析。研究结果表明:所设计的视觉传感系统可有效提取焊接图像特征,识别精度高。焊缝跟踪系统可实时校正焊枪位置,焊枪高度误差始终保持在0. 2 mm以内,焊缝角度识别误差不超过0. 4°,说明该系统抗干扰能力强,焊接精度高,实时性好。     

基于激光双目视觉的接缝三维重建

设计研制了结构激光双目视觉传感器,该传感器加入结构激光,很好地解决了立体视觉中对应点的匹配问题.利用该传感器采集接缝图像,开发了图像采集处理程序,实现接缝图像处理和特征分析,识别并提取了二维平面上接缝特征点的图像坐标.采用MATLAB软件实现了三维重建标定算法,根据双目视觉原理,由接缝特征点的图像坐标计算出其三维坐标,进行了三维重建,抽取了接缝三维几何尺寸、坡口类型、角度、间隙等焊接特征信息.     

基于工业机器人的图像引导圆孔定位方法

在图像引导的圆孔金属工件自动化装配中,由于圆孔金属工件的图像存在弱纹理甚至无纹理的情况,从而导致对圆孔位姿的定位精度低。针对此问题,通过工业机器人带着单目工业相机水平移动构建一个平行双目结构,获取双目图像;通过对双目图像中的圆孔轮廓提取的特征点粗匹配,得到图像的基础矩阵,再通过基于弧段的椭圆检测对双目图像中的圆孔轮廓进行提取,最后通过上述信息进行基于极线约束的双目精立体匹配并求得相关点三维坐标与位姿。实验结果表明：孔位与孔心距精度保持在1 mm内,孔姿态精度保持在0.3°内。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.