金属薄板焊接过程中的复杂变形会对其尺寸精度、装配精度和使用性能造成显著影响,在焊中和焊后对金属薄板变形进行测量,对于了解材料的变形机理、改善焊接工艺、减少焊后应力和变形,以及提高焊件的承载能力具有重要的理论意义和工程价值。针对金属薄板焊接变形测量难题,提出了一种融合近景摄影测量和立体视觉技术的视频测量方法,通过重建并跟踪粘贴在金属薄板表面标志点的三维坐标,计算相应部位在焊接不同时刻的位移,获得金属薄板在焊接工艺中的整体变形过程和瞬时变形场域信息。通过精度评估实验得知,该方法的三维坐标测量精度高于0.05mm;通过焊接变形测量实验得知,该方法能够满足焊接过程三维变形测量对精度和效率的要求。
To overcome the problem of rapid 3D deformation measurement in metal sheet welding experiments, a non-contact opti- cal measuring method was proposed. Based on Close Range Photogrammetry(CRP) technology and Stereo Vision (SV), this meth- od employs two industrial-class CCD camera to capture image pairs of artificial markers pasted on metal sheet surface, calculates 3D coordinates of these markers through analyzing the image pairs in each epoch. By tracking variations of the 3D coordinates of the markers ,the 3D deformation distribution of the metal sheet is obtained, which is helpful for further analyzing static and dy- namic behaviors of the structures. Acceptance experiment results indicates that the accuracy of this method could reach 0.05mm for measuring a moving object. Welding experiment shows that the proposed method could satisfy the efficiency and accuracy re- quirements in metal sheet welding deformation measurement.