一种对薄板焊接全场变形的图像测量方法

发布时间：2019-06-29 09:46

【摘要】：为解决焊接过程中由于高温高亮而使焊件变形难以测量的问题,采用改进的数字图像相关法和双目立体视觉对金属薄板焊接全场变形进行测量。对弱相关图像匹配的解决方法和数字图像相关的算法进行分析,并通过去噪和分段基准保证弱相关图像的正确匹配:首先,使用高斯平滑对原始图像进行去噪处理,消除焊接强光干扰;然后,采用分段建立基准的方法解决了焊点区域因散斑质量下降而出现的难以匹配的问题。对Newton-Raphson算法的二阶梯度矩阵进行简化,提高相关计算的速度。在测量实验中,首先对板料表面进行预处理与散斑制备,然后在氩弧堆焊(TIG)过程中利用高速相机拍摄板料焊接及冷却自由变形的全过程,最后计算所有图像中变形点的位移,获得板料特别是焊缝区的全场变形数据。研究结果表明:将此方法应用于焊接变形测量,能得到整个焊接过程中任意点的变形曲线,并且可在高温焊缝区获得准确的变形趋势。测量结果可用于分析影响焊接变形的因素,进而对焊接变形实施控制,也可用于检验焊接变形数值模拟方法的正确性。
[Abstract]:In order to solve the problem that the deformation of welding parts is difficult to be measured due to the high temperature highlighting in the welding process, the improved digital image correlation method and binocular stereo vision are used to measure the whole field deformation of metal sheet welding. The solution of weak correlation image matching and the algorithm of digital image correlation are analyzed, and the correct matching of weak correlation image is guaranteed by denoising and segmented reference. Firstly, Gaussian smoothing is used to Denoise the original image to eliminate welding strong light interference; then, the method of piecewise benchmark is used to solve the problem of difficult matching in solder joint area due to the decrease of speckle quality. The second-order gradient matrix of Newton-Raphson algorithm is simplified to improve the speed of correlation calculation. In the measurement experiment, the surface of sheet metal is pretreated and speckle prepared, and then the whole process of free deformation of sheet metal welding and cooling is photographed by high speed camera in the process of argon arc surfacing (TIG). Finally, the displacement of deformation points in all images is calculated, and the whole field deformation data of sheet metal, especially in weld zone, are obtained. The results show that the deformation curve of any point in the whole welding process can be obtained by applying this method to welding deformation measurement, and the accurate deformation trend can be obtained in the high temperature weld zone. The measurement results can be used to analyze the factors that affect the welding deformation, and then to control the welding deformation, and can also be used to test the correctness of the numerical simulation method of welding deformation.
【作者单位】：西安交通大学机械工程学院机械制造系统工程国家重点实验室;广东顺德西安交通大学研究院;
【基金】：国家自然科学基金资助项目(51675404,51421004) 广东省公益研究与能力建设专项资金资助项目(2014A010104003)~~
【分类号】：TG404;TP391.41

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