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1.
针对厢体焊接涉及多种类型焊缝,提出了一种焊缝类型识别方法. 采用激光条纹提取算法获取焊缝骨架,对焊缝骨架进行直线拟合,求取焊缝骨架特征点作为兴趣点,利用多尺度形状描述符对兴趣点进行特征描述,获取焊缝类型的形状信息. 选取多种类型焊缝模板,通过模板匹配算法进行焊缝类型识别. 结果表明,焊缝类型分类正确率可达95%以上,这种焊缝类型识别方法是可行的.  相似文献   

2.
在对接焊缝的焊后质量检测中,由于环境干扰、材质反射程度及激光功率等因素的影响,造成焊缝表面信息的提取困难。针对上述问题,提出了一种基于线结构光的铝合金对接焊缝特征提取方法,设计了一种基于线结构光的视觉检测系统,实现焊缝表面激光条纹图像的快速采集。针对复杂环境下激光条纹图像的几何分布以及灰度特征,采用直线重投影、图像滤波、连通域分析等图像预处理操作,实现焊缝图像的ROI提取以及噪声滤波;采用加权灰度重心法提取激光条纹的中心线,并通过插值平滑算法得到连通性、拟合程度高的中心线;最后采用最大距离法得到对接焊缝特征点,并计算所需焊缝成形尺寸参数。试验结果表明,该方法能够有效提高图像检测效率及精度,满足工业检测标准。  相似文献   

3.
在薄板焊接过程中,由于环境光干扰、物体表面反射和激光散射等因素的影响,采集的图像中噪声密度过大,造成焊缝中心难以准确提取。针对上述问题,提出了一种基于视觉传感的薄板对接焊缝特征提取方法,设计了一种基于线激光的视觉传感系统,实现对薄板表面激光条纹图像的快速采集。针对复杂环境下激光条纹图像的灰度特征,采用图像二值化和自适应中值滤波算法去除图像中的噪声,利用重心法和统计列像素点个数方法选取ROI区域;通过对ROI区域图像进行阈值分割、开运算和提取重心得到激光条纹中心线;最后采用二阶差分法和极值搜索法得到对接焊缝特征。实验结果表明,该方法能够有效去除噪声干扰,准确提取焊缝中心及对接焊缝宽度。  相似文献   

4.
一种焊缝结构光图像处理与特征提取方法   总被引:1,自引:1,他引:0       下载免费PDF全文
李原  徐德  沈扬  谭民 《焊接学报》2006,27(9):25-30
提出了一种焊缝结构光图像处理与特征提取方法,有效克服了焊缝结构光图像中的反光等干扰,准确提取图像中焊缝位置特征.对于激光条纹中心线的提取,采用基于图像列方向像素灰度分布的曲线峰值提取方法,并利用激光条纹位置在时间和图像空间上的连续性和相关性,进行判断提取.对于焊缝图像特征的提取,根据沟槽类焊缝图像形状特点,选择焊缝沟槽图形中心作为图像特征.焊缝图像处理与焊缝跟踪试验结果证明了该方法的有效性和可靠性.  相似文献   

5.
提出一种基于新的单目视觉线性结构光的膜式壁焊缝识别方法,克服了焊接过程中的飞溅、烟雾等干扰,快速地提取了膜式壁角焊缝特征点。首先,根据激光条纹图像与背景的显著性差异,采用灰度级频率法提取了激光条纹图像;其次,基于骨架抽取提取了激光条纹中心线,并对中心线坐标应用Takagi Sugeno模糊算法进行滤波;最后,应用动态ROI搜寻法快速找到含有焊缝特征点的区域,结合快速排序算法找到焊缝特征点坐标。经实验证明,该算法能够快速准确地提取焊缝特征点,结合控制算法,能够准确跟踪焊缝。  相似文献   

6.
基于结构光视觉传感的焊缝视觉信息检测和识别研究   总被引:2,自引:0,他引:2  
对基于结构光视觉传感的焊缝视觉信息检测和识别进行了研究.所获取的焊缝图像中存在着大量的飞溅、烟尘和电弧光等噪声干扰.CCD摄像机获取焊缝图像,经图像采集卡A/D转换后送入计算机内存,然后采用各种图像处理方法对图像数据进行处理,焊缝原始图像经过二值化、中值滤波、拉普拉斯锐化、细化一系列图像预处理,准确提取激光条纹信息,提出了几种常见的焊缝形式的检测和识别算法,算法所需时间均不到1 ms,提取焊缝特征,实现对焊缝的自动跟踪.  相似文献   

7.
不锈钢薄板激光焊焊缝成形尺寸细微,焊接速度快、节拍快,人工进行焊缝缺陷检测已不适合,因此焊缝缺陷检测的自动化是必然趋势。构建了一套激光焊焊缝数字成像(DR)检测系统,并在DR检测图像的基础上研究了焊缝缺陷的自动检测与识别算法。首先设计焊缝和焊接缺陷检测系统,可靠地将焊缝和焊接缺陷从工件背景中分割出来,基于此又设计了焊接缺陷特征提取算法和缺陷类型识别算法,通过二叉树和逻辑回归分类可以将激光焊焊缝中的常见缺陷识别出来,识别正确率达到了工程化水平。  相似文献   

8.
双线激光传感焊枪定位与焊缝走向识别   总被引:3,自引:3,他引:0       下载免费PDF全文
为实现焊接机器人焊枪定位与焊缝走向识别,提高焊缝跟踪精度,提出了一种交叉式双条纹激光传感方式,建立了该传感方式下双条纹激光间距与焊枪高度关系的理论模型.按图像行上灰度值和的一阶导数提取感兴趣区域(region of interest, ROI)、最大类间方差阈值分割及Canny边界提取等处理后,获得了上下激光条纹中心间距离及坡口中心值,由理论模型计算得焊枪高度,上下坡口中心值获得焊缝精确偏差与焊缝轨迹走向.结果表明,建立的理论模型正确,该方法可快速实现焊枪准确定位,识别焊缝轨迹走向,减小导前误差,提高偏差识别精度和焊接机器人智能化程度.  相似文献   

9.
针对多层多道焊标准与非标准打底焊缝及各道填充焊缝在激光辅助视觉下的图像信息,提出了一种基于距离滤波的图像处理算法来快速、准确识别出焊缝特征点。该算法首先对激光条纹图像进行二值化、开运算等预处理;对预处理后的图像按列扫描,利用重心法提取激光条纹中心线,针对中心线出现断点的情况,通过直线拟合来填充断点;然后选取中心线上若干点拟合直线,通过求中心线上点到直线的距离,对中心线上的点进行3次滤波处理,滤除中心线上大量与特征点无关的点;最后快速找到中心线上4个端点并进行距离补偿得到焊缝的4个特征点。试验结果表明,该图像处理算法能快速、准确识别出焊缝特征点,为多层多道焊缝跟踪提供了重要依据。  相似文献   

10.
由于棱形管与法兰角焊缝的位置多变,且实际生产中棱形管端面加工精度不高,自动化焊接程度低,文中搭建了一套棱形管与法兰环焊缝的自动化焊接系统,对于提高棱形管与法兰焊接的自动化程度有较大的应用价值。该系统通过CMOS相机和单条纹激光组成激光视觉传感器,获取角焊缝位置和间隙信息。针对采集的图像及工件特征,设计了适合的图像处理算法,首先采用了灰度变换、均值滤波和形态学处理的方法对图像进行预处理,然后根据对激光条纹图像灰度值分析结果,寻找合适的阈值,并采用极值法提取光条中心点,最后采用霍夫变换拟合直线,提取出角焊缝位置信息,并提出激光条纹端点搜索方法,提取出了角焊缝间隙大小。结果表明,该图像处理方案效果较好,抗干扰能力较强,可以准确的提取出焊缝中心位置和间隙大小,满足焊接机器人对焊缝跟踪的要求以实现自动化焊接。 创新点: (1)设计出适用于棱形管与法兰角焊缝的自动化焊接系统。 (2)设计了适用于该系统的焊缝中心位置提取算法。 (3)设计了角焊缝间隙提取算法。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

14.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

15.
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).  相似文献   

16.
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.  相似文献   

17.
This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.  相似文献   

18.
Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.  相似文献   

19.
A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.  相似文献   

20.
韩磊 《腐蚀与防护》2015,36(1):84-90,94
综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。  相似文献   

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