移动焊接机器人坡口自寻迹的切人角算法

为正确建立位姿调整轨迹规划的坐标系，研究了移动机器人在自寻迹过程中的关键问题——切入角的计算．结合工程应用实际，基于激光视觉传感器并根据不同的焊接坡口形式提出了3种切入角算法，同时分析了每种算法的利弊和适用场合，并重点讨论了激光视觉传感器扫描坡口方式的切入角算法．该算法不严格依赖坡口加工精度，也不需要知道确切的坡口形式，提高了算法的实用性和可靠性．试验结果表明，所提出的3种切入角算法是切实有效的，能够满足实际焊接工程需要．     

基于组合激光结构光的视觉传感器检测算法及图像处理流程优化

基于激光结构光的视觉传感器广泛应用于焊接领域的坡口检测和焊缝跟踪。该文提出了一种基于组合激光结构光的新型视觉传感器,独特的光路结构设计避免了传感器应用于不同焊接位姿时繁琐的外参数标定,仅依靠传感器内部固有参数(应用前需校准)和焊接坡口图像的特征点坐标值,即可实现焊接坡口参数的在线检测,有效增强了传感器的适应性。通过对不同图像处理算法的改进和合理组合,对图像处理流程进行了优化。动态感兴趣区(region of interest,ROI)区域提取算法可快速寻获有价值的激光线和特征点所在区域,有效提升了后续图像处理速度;顶帽变换与自适应二值化组合,在将激光线灰度值均匀化的同时,实现了激光线与背景图像的有效区分。运用基于LOG(Laplacian of Gaussian)算子的边缘识别算法,可提取出激光线的单像素边缘;采用最小二乘法对所求得的激光中心线离散点进行直线拟合,通过联立直线方程求交点的方式,实现了对焊接坡口特征点图像坐标值的准确识别。借助Visual Studio平台,运用改进的图像处理算法、优化的图像处理流程和检测算法,对特征参数不同的V形焊接坡口进行检测试验,检测误差均在±4%以内,验证了所提出视觉传感器及其检测算法和图像处理流程的合理性和适用性。     

中厚板变坡口焊接轨迹规划算法

针对变坡口工件焊接的需要,提出了一种多段线拟合的变坡口中厚板焊接轨迹规划方法。利用线激光传感器完成变坡口截面的扫描测量,并利用斜率比较法对测量得到的坡口截面数据进行拟合处理,从而将离散不规则的坡口拟合为较为规整的便于实际焊接加工的多段线坡口。从MATLAB仿真分析结果可以看出,该方法可以满足变坡口截面轨迹规划的需要,具有较好的实用价值。     

窄间隙旋转电弧熔化极活性气体保护焊视觉焊缝偏差检测

摘要： 针对旋转电弧窄间隙熔化极活性气体保护焊多层单道焊焊缝跟踪需要,提出一种基于被动视觉传感的焊缝偏差识别方法. 首先通过旋转电弧位置传感器和处于触发工作模式的CCD摄像机获取电弧旋转到坡口左侧和坡口右侧时的焊接图像,然后根据图像灰度直方图特点,构建了自适应双阈值获取算法. 大阈值用于获取电弧区域进而得到电弧中心位置;小阈值用于获取坡口工件区域,进而通过计算水平方向一阶差分得到坡口边缘. 通过对比一个电弧旋转周期内获取的两幅图像,可计算电弧旋转中心和坡口中心的偏差,得到焊缝偏差. 该偏差检测算法高效、可靠且可避免坡口底部改变带来的误差,同时可用于不同偏差算法的比较和融合.     

用于弧焊过程的视觉传感图像处理及特征信息提取方法

视觉传感是获取焊枪位置和姿态以及焊接坡口形状和尺寸等特征信息的有效手段,是实现弧焊过程闭环反馈控制和智能化焊接的基础.该文提出了用于弧焊过程的视觉传感图像处理及特征信息提取方法.研发了基于视觉与重力融合的多源传感器;为有效降低弧焊环境的强弧光及飞溅等对CCD图像的干扰,优化了相关硬件和图像预处理算法,改进并实现了基于C...     

采用激光线光源的焊接坡口间隙视觉检测

针对生产过程中焊件的加工装配误差、焊件热变形等因素导致的焊接坡口间隙变化从而影响焊缝质量的问题,设计基于激光线性光源的焊接坡口间隙视觉检测系统.运用LabVIEW的Vision Builder AI 3.0图像处理模块对焊接坡口间隙变化进行实时测量,实现坡口间隙变化视觉信号的图像采集和检测.实验表明,焊接坡口的检测精度和实时性可以满足焊枪姿态、焊枪摆动角度和焊接过程中焊接规范的实时修正与控制要求.     

一种基于结构光的V型坡口焊缝特征点识别算法

针对典型的V型坡口焊缝,采用自主研发的激光视觉传感系统设计了一种基于投影拟合方法的焊缝特征点识别算法,并通过实验加以验证.结果表明,所提出的算法对焊缝特征点的提取精度较高.     

信息融合技术在激光-TIG焊接监控过程中的研究

阐述了多传感器信息融合理论,结合卡尔曼滤波原理,提出了卡尔曼滤波融合算法,并将此算法应用于激光焊接质量控制过程中.理论分析和计算机仿真验证表明,该算法能获得平缓的控制特性,可以有效提高激光焊接过程的监控性能.     

工程实例中伸缩节厚壁件焊接工艺的应用

在水利电力工程中实际应用了伸缩节坡口形式、焊接快捷、检测结果优良,很好地保证了伸缩节焊接质量的要求。焊接方法及焊接电流参数的应用,为今后相同的工程的施工具有参考价值。     

基于激光视觉的多层多道焊接坡口特征点提取方法

多层多道自适应焊接一直是实现中厚板焊接自动化的难点.文章研究了多层多道焊焊接坡口特征点提取方法,通过对焊接坡口激光条纹图像特征分析,首先采用中值滤波去除图像噪声,利用阈值分割和重心法提取激光条纹中心线,然后经过中心线拟合直线求交点和逐列搜索对比获取焊接坡口轮廓的四个拐点,为后续多层多道自适应焊接提供了可行性技术途径.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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