Research Of Three-dimensional Reconstruction Of Corrugated Board Weld Seam Based On Laser Binocular Vision For Arc Welding Robot

As one of non-contact measuring methods, the binocular vision has been widely used inweld seam detection for its high precision and ability of avoiding interference. The weldseam tracking system, which comprises the visual sensor and welding robot, can trace theweld seam with less teaching programming and high self-adaptively of robot and it is anefficient way of improving the intelligent level of robot and welding automation. Laserbinocular vision techniques are applied for computing the three-dimensional information ofcorrugated plate weld seam. Three-dimensional reconstruction of welding trajectory inrobot base coordinate system has very important practical significance to weldingautomation of corrugated plate.A laser transmitter and two CCD industry cameras are mounted on the end-effecter ofrobot, to observe the welding environment. The three-dimensional information ofcorrugated plate weld seam is computed based on the principle of binocular vision. Firstly,the theories of imaging principle, calibration methods of binocular vision system and roboteye-hand system are researched. Combined the theoretical analysis with the Matlab"calibration toolbox", we calibrated the binocular vision system and hand-eye system basedon the calibration board images. Secondly, an algorithm, which can be used to search alongthe laser stripe with variable step lengths after image preprocessing, is proposed forsearching corrugated plate welding seam feature point. The three-dimensional (3D)coordinates of spatial weld seam thus can be reconstructed in real time based on a programcalled "3D information acquisition of corrugated plate welded seam and seamreconstruction".The experimental results show that laser binocular vision can detect the structurecharacteristics and turning points of corrugated plate with high accuracy. Thethree-dimensional reconstruction error of welding trajectory in robot base coordinates isless than1mm.The visual computing error, robot geometry model error and hand-eyecalibration error have impact on the three-dimensional reconstruction to a certain extent.