In the seam tracking for the metal active gas (MAG) welding of heavy plate, there are many problems, such as the strong arc light due to the large current, spatter and fumes, the losses of centerline information and complex conditions in groove induced by previous passes, etc. The problems often make the characteristic in the images needed for seam tracking indistinct and make it difficult for industrial robots to correct the deviation of multi-pass welding. Regarding this issue, a robotic seam tracking system based on vision sensing and human-machine interaction for the multi-pass MAG welding was proposed. The groove edges were used as reference to tell the deviation and to control it according to a simple, fast and effective control strategy based on human-machine interaction. The deviation could be judged by comparing the left or right groove edge alternatively with the corresponding specified positioning ruler from the real-time images obtained by industrial camera. The operators could adjust the torch position in real time by the hint on the positioning ruler, which followed the control strategy. The accuracy, response rate and smoothness of the system were verified by reasonable path planning in multi-pass MAG welding. By comparing the deviation correction of robot with the actual deviation of weld seam, the accuracy of system was rated, which had an average error less than 0.5 mm and was acceptable. The comparison between the actual weld height and width after correction and the designed height and width showed that the system worked smoothly and steadily and the system could track the weld in real time.

在厚板金属活性气体（MAG）焊接的接缝跟踪中，存在许多问题，例如由于大电流，飞溅和烟气而产生的强电弧光，中心线信息的损失以及由沟槽引起的凹槽中的复杂条件。这些问题通常会使接缝跟踪所需的图像特征不清楚，并使工业机器人难以校正多道次焊接的偏差。针对这一问题，提出了一种基于视觉传感和人机交互的机器人焊缝跟踪系统，用于多道MAG焊。凹槽边缘被用作判断偏差并根据基于人机交互的简单，快速和有效的控制策略对其进行控制的参考。可以通过将左或右凹槽边缘与相应的指定定位尺进行比较，从而根据工业相机获得的实时图像来判断偏差。操作员可以通过定位尺上的提示实时调整割炬位置，并遵循控制策略。通过合理的多道MAG焊路径规划，验证了系统的准确性，响应率和平滑度。通过将机器人的偏差校正与焊缝的实际偏差进行比较，对系统的精度进行了评定，其平均误差小于0.5 mm，是可以接受的。校正后的实际焊缝高度和宽度与设计的焊缝高度和宽度的比较表明，该系统运行平稳，稳定，并且可以实时跟踪焊缝。