共查询到20条相似文献,搜索用时 62 毫秒
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在由CCD捕获的CO2焊接熔池图像中,存在着大量的点状噪声和线状噪声,要精确地检测出熔池图像的边缘比较困难.采用基于数学形态学理论中的灰度形态学数字图像处理技术,结合焊接熔池图像自身的特点,借助灰度图像二值化取阈值法中的矩量保持法确定结构元素值的大小,通过合理设计形态学滤波器形状和运算顺序,成功地提取出了焊接熔池图像的边缘,通过比较,新的图像处理算法的处理效果非常明显,对后续的焊接质量控制和焊缝跟踪工作提供了非常有用的熔池信息. 相似文献
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轮廓提取作为熔池的基本视觉形态特征,在焊接质量在线监测中起着重要作用. 文中建立了非熔化极惰性气体保护电弧焊(tungsten Inert gas welding, TIG)焊接工艺环境下的熔池视觉传感系统,采集了高质量的熔池图像. 针对TIG焊不锈钢熔池图像中弱边缘检测的难点提出了一种基于边缘导向算子模板匹配的熔池轮廓提取算法(operator template matching based on edge direction guidance, OTM-EDG),算法中首先基于非线性灰度变换方法增强弱边缘. 之后利用4个方向的Sobel算子与熔池图像进行卷积操作来判断后端弱边缘的方向并计算梯度图. 最后对梯度图进行边缘连接操作以及基于数学形态学的边缘平滑操作,得到需要提取的熔池轮廓. 结果表明,文中算法能够提取到封闭完整且定位准确的TIG焊不锈钢熔池轮廓. 在实际焊接环境中具有较高的鲁棒性,有效解决了熔池区域弱边缘难以准确检测的问题. 相似文献
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脉冲熔化极气体保护焊熔池图像的检测与处理 总被引:12,自引:5,他引:12
利用CCD摄像机和复合滤光技术建立了一套熔池图像实时采集系统。利用光谱分析,提出了适合于脉冲熔化极气体保护焊(P-GMAW)熔池成像的滤光光谱窗口,并对中心波长分别为665nm和1064nm滤光系统的成像质量进行了分析。分析了P-GMAW单个脉冲内的不同时刻的熔池图像,研究表明脉冲基值结束期间为最佳的取像时刻。使用中心波长为665nm的滤光系统,从熔池正后方取像,获取了清晰的熔池图像。针对所获取的典型的P-GMAW熔池图像,详细研究了其成像机理。开发了一套熔池图像处理程序,利用该程序提取了完整的熔池轮廓。 相似文献
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研究对脉冲熔化极气体保护焊(GMAW)熔池过程采用视觉传感与实时控制方法的可行性问题。由于GMAW过程的熔滴过渡现象的复杂性,尝试模拟焊工通过观察熔池变化等因素来调整焊接参数获取满意的焊缝成形的行为。建立了脉冲GMAW过程熔池视觉传感系统,宏观上将熔滴过渡对熔池特征的影响作为黑箱过程处理,根据脉冲GMAW弧光光谱分布和熔池图像特征提取,实现对脉冲GMAW熔池动态过程的实时检测。采用辨识算法建立焊接动态过程的数学模型,进而设计脉冲GMAW熔宽的PID控制器,实现对脉冲GMAW熔池宽度的实时控制。试验表明,建立的视觉传感系统、图像处理算法以及控制器设计检测与控制熔池变化在一定程度上的能够满足脉冲GMAW焊缝宽度的实时性与精度要求。 相似文献
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07MnCrMoVR钢是石化行业用于球罐制造的常用材料,对该材料采用熔化极气体保护焊工艺,结合球罐制造的设计条件,研究了焊接接头的常规力学性能、无塑性转变温度、断裂韧性及金相组织,试验取得了满意的效果. 相似文献
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采用双椭球体热源分布模式,把过热熔滴带入熔池的热焓量处理为特定区域的均匀热源,建立了运动电弧下熔化极气体保护焊热过程的数值分析模型.利用VisualFortran编写数值计算程序,预测了从电弧引燃到准稳态过程中焊接温度场和熔池形状的动态演变,以及自由表面的变形,并进行了对比试验.结果表明,达到宏观准稳态时所得的熔池宽度与深度与试验结果基本吻合. 相似文献
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对等离子弧焊接熔池图像边缘提取算法进行了研究.拍摄了等离子弧焊接正面熔池,发现强烈的正面电弧弧光被熔池液态金属表面反射后在图像中形成大面积的灰度饱和区,弧光区域边界的灰度梯度远大于真实熔池边缘的灰度梯度,导致常规的图像处理算法不能准确地将熔池边界提取出来.针对这一问题,提出多经验参数约束的边缘检测算法,使用前n幅已处理熔池图像边缘信息和弧光最小外接曲线等多种经验参数作为引导信息对图像边缘进行约束,剔除伪边界,检测出真实的熔池边缘信息.将所提取的边缘信息与试验测量结果进行比较,表明所提出的算法能够有效快速地检测出熔池边缘. 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):407-414
AbstractA three-dimensional model has been developed to study turbulent fluid flow and heat transfer in a gas metal arc weld pool. The phase change process during melting and solidification is modelled using the enthalpy–porosity technique. Mass and energy transports by droplet transfer are considered through a thermal analysis of the electrode. The droplet heat addition into the molten pool is considered to be in the form of a volumetric heat source distributed in an imaginary cylindrical cavity within the weld pool ('cavity' model). A two-equation k-ε model capable of addressing turbulent weld pool convection, taking into account the morphology of the phase change, is presented. The weld pool dynamics and geometry (shape and size) in a moving gas metal arc welding (GMAW) process are studied and the effects of enhanced diffusivities on the turbulent weld pool are discussed. The predicted weld pool geometry using laminar and turbulent models is also compared with corresponding experimental post-weld sections. 相似文献
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针对GMAW短路过渡焊接过程的熔池视觉检测,采用普通工业CCD摄像机,通过光谱分析选择窄带复合滤光器。设置了CCD摄像机曝光时间,分析短路过渡电压波形,确定了CCD摄像机采集时刻并设计了短路检测及CCD摄像机外触发电路,准确地将CCD摄像机的曝光时刻定位于短路过渡阶段。提出了正前方小角度和正后方大角度的图像采集方式。结果表明,采用以上图像采集方案,利用普通工业CCD摄像机可拍摄到连续清晰且不失真的熔池图像。并设计了图像处理算法,提取出完整的熔池边缘。 相似文献
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《Science & Technology of Welding & Joining》2013,18(1):41-50
AbstractA model has been developed that correlates the anode temperature profile with the dynamic melting rate in gas metal arc welding. The components of this model are the electrode melting rate, the temperature dependent resistivity of the electrode, and the arc voltage. The differential equations describing the dynamic behaviour of the electrode extension were derived from the mass continuity and energy relations. The temperature of the electrode extension was determined by analysing conductive heat transfer and Joule heating effects. Onedimensional solutions for the temperature and heat content were used to obtain the dynamic melting rate equation. The purpose of the present paper is to provide quantitative analyses, concentrating on the thermal behaviour and the electrical characteristics of the arc welding system, to aid in achieving a fundamental understanding of the process, and to develop a dynamic model that can be used in adaptive control. The model is tested by comparison with experimental results. 相似文献
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In manual welding process, skilled welders can adjust the welding parameters to ensure the weld quality through their observation of the weld pool surface. In order to acquire useful information of the weld pool for control of the welding process and realizing the automatic welding, the measurement system of DB-GMA W process was established and the weld pool image was obtained by passive vision. Then, three image processing algorithms, Sobel, Canny, and pulse coupled neural network (PCNN) were detailed and applied to extracting the edge of the DB-GMA weld pool. In addition, a scheme was proposed for calculating the length, maximum width and superficial area of the weld pool under different welding conditions. The compared results show that the PCNN algorithm can be used for extracting the edge of the weld pool and the obtained information is more useful and accurate. The calculated results coincide with the actual measurement well, which demonstrates that the proposed algorithm is effective, its imaging processing time is required only 20 ms, which can completely meet the requirement of real-time control. 相似文献