机器人水下焊缝跟踪中双目立体视觉系统

根据机器人水下焊缝跟踪的要求,设计了一套双目立体视觉传感器.采用卤钨灯辅助光源加复合滤光系统,较好地去除了噪声,拍摄到较为清晰的焊缝图像.针对水下焊缝图像模糊、对比度低的特点,采用模糊增强图像处理技术,对Pal处理算法进行了改进,改进算法中采用OTSU法选择最佳阚值,提出了新的隶属度函数.试验表明,该算法提高了图像处理的效率,提取的边缘比较精细,为空间焊缝跟踪中焊缝识别及立体匹配奠定了基础.     

基于双目视觉的水下对接焊缝跟踪机器人位姿调节

分析了机器人末端姿态调节原理,利用所搭建的双目视觉系统采集到水下对接焊缝图像,图像经过滤波去噪、模糊增强、图像边缘特征及检测后,获取两条边缘线的特征元素。根据这两条边缘线求出水下对接焊缝中心线,再找到中心线上的匹配点;根据匹配点前后扫描,得到与焊缝边缘线相交的四点,采用四点法求取水下对接焊机器人的末端位姿。最后根据所构造的焊枪位姿与机器人位姿的模型,得到焊枪的姿态。试验证明,本文提出的算法,位姿调节偏差较小,能满足水下对接焊缝跟踪的要求。     

水下焊接机器人视觉传感系统图像干扰因素分析

水下焊接机器人视觉传感系统在焊接过程中实时的对焊缝图像进行提取,通过一系列的图像处理算法,识别出焊缝位置,得到焊缝与焊枪之间的位置偏差,通过控制算法,实现焊缝跟踪的目的.在图像提取的过程中,会有各种各样的干扰,如泥沙干扰、弧光干扰、水泡气泡干扰、水对光的散射等各种干扰.着重分析了水下焊接机器人视觉传感系统图像提取的各种干扰因素,并对各种干扰因素产生的原理加以研究分析,并在此基础上,对如何去除各种干扰因素的方法--"二步干扰因素去除法"进行了简要的分析.     

药芯焊丝水下焊接焊缝跟踪视觉传感系统的设计

为满足药芯焊丝水下焊接自动化的需要,研究了用于水下焊缝自动跟踪的视觉传感系统。该系统较好地解决了药芯焊丝水下焊接弧光对焊缝图像传感的干扰问题,能获取较清晰的焊缝图像。采用基于图像分割的边缘检测技术成功地提取了焊接电弧和待焊焊缝的边缘,使用该系统可获得电弧和待焊焊缝的偏差信息,为进上步实现药芯焊丝水下焊接焊缝的自动跟踪控制打下了基础。     

水下焊缝自动跟踪路径的识别

为满足水下焊缝自动跟踪的需要,设计了一个视觉系统。该系统采用卤钨灯作辅助光源照射焊接电弧前方一定距离处的待焊焊缝．配合复合滤光片进行滤光,能拍摄到较为清晰的焊缝图像。提出了一个基于边缘邻域平均值的算子,用于图像的边缘增强。运用改进的遗传算法计算图像类间方差,求出最佳阈值进行图像边缘分割,能较好地保留图像弱边缘．有效地减少计算时间。对分割后的焊缝图像,提出一种基于待焊焊缝宽度等特征的识别方法,能克服焊接弧光、飞溅、水流、气泡等干扰,识别水下待焊焊缝．准确地获取待焊焊缝中心线．为进一步实现水下焊接的自动化打下了基础。     

大型构件水下焊接机器人系统

针对水下焊接环境要求,设计了一种履带式水下焊接机器人系统,该系统由机器人本体机构、激光视觉传感器、控制系统和焊接系统组成. 机器人本体机构由履带式移动平台和焊枪调节机构构成,运动灵活可靠,满足水下焊接焊缝跟踪要求. 完成了视觉传感器部件选型及光路设计,实现水下环境的焊缝自动识别. 设计了基于PLC机器人控制系统和协调控制方法,实现水下环境的焊缝跟踪控制. 同时在水下焊接试验平台完成焊接跟踪试验. 结果表明,机器人运行稳定,焊缝成形较好,焊接质量满足要求.     

一种基于先验知识的弧焊机器人图像处理方法

在弧焊机器人视觉检测的CCD直接拍摄图像方法中,针对带有黑笔记号、划痕、并与焊缝交叉干扰的复杂对接焊缝图像,文中提出了一种实用的焊缝轨迹的识别方法,并对该算法中的骨架细化及边缘链的拆分、合并剪枝和基于先验知识的位置关系判断等关键问题进行重点阐述. 结果表明,该算法能有效地去除复杂焊缝图像中的黑笔记号、划痕和交叉干扰,最终自动提取焊缝轨迹. 该算法具有较强的适应性和可扩展性,稍加改进就可应用于其它复杂图像上. 如带电弧光或结构光等的图像. 该算法能为弧焊机器人视觉检测的智能化的进一步提高提供一定的技术参考.     

Snake模型和遗传算法在特殊焊缝提取中的应用

针对CCD直接拍摄图像的弧焊机器人焊缝视觉检测问题,文中提出了一种精确提取带有较大的间断、尖锐的拐点、较多的干扰等特殊焊缝轨迹的算法.该算法先用小波变换进行焊缝边缘线的平滑,得到与最终焊缝距离很近的初始焊缝轨迹,再用基于Snake模型和遗传算法的进行特殊焊缝的精确匹配和提取.结果表明,该算法能进一步提高特殊焊缝轨迹识别的识别和检测精度,具有较强的适应性,也为弧焊机器人视觉检测的智能化的进一步提高提供一定的技术参考.     

比例模糊滑模控制在焊缝跟踪中的运用

针对单纯的模糊控制器在焊接机器人的焊缝跟踪中的控制精度欠佳、自适应性不强等问题,设计了一种新的用于水下焊接机器人焊缝跟踪的比例模糊滑模控制器.控制器采用基于某阈值的切换方法.当焊缝偏差>4mnl时,采用P控制,提高系统的响应速度;当偏差<4 mm时,采用模糊滑模控制,实现平滑跟踪,且鲁棒性好.通过对系统仿真和试验,获得很好的焊缝跟踪效果.     

水下焊接中无弧V形焊缝的识别

设计了一个水下焊接自动跟踪视觉系统,其主要由激光器、滤光片和CCD摄像机组成,被封装在防水的透明玻璃体中.焊接时激光器作为辅助光源,其与CCD成30°照射焊件,得到焊件的V形剖面焊缝.由于水下焊接时拍摄的图像模糊且比较弱,采用中值滤波的方法进行图像增强,然后进行阈值变换得到焊缝,再用Krisch边缘算子对焊缝进行边缘提取,提出了对边缘的灰度值取平均值得到焊缝中心线,最后对其进行直线拟合,提取V形焊缝的中心线所在的最低点,画出中心线以进行标识.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.