Passive vision based seam tracking system for pulse-MAG welding

Welding robots have been widely used in manufacturing process to substitute for human welders. However, most of them are rigid and cannot adjust to variations in the weld seam positions caused by natural welding environmental factors. To address this problem, this paper presents a passive vision-based robotic welding system, which can realize the seam tracking function for pulse-MAG welding. In this paper, the light spectrum of the welding process is analyzed to determine the optical filters used during the image capture. Then, a robust image processing method is proposed to extract the offset from the image which contains much noise. The transformation formula is calibrated to obtain the relationship between the image coordinate system and the robot coordinate system. The tracking strategy is designed to improve the tracking precision and the stability of the welding process. Finally, experiments are conducted on straight line and curved line seam to verify the feasibility of the developed system.

[1]  T. Lin,et al.  Research on weld pool control of welding robot with computer vision , 2007, Ind. Robot.

[2]  Sang Bong Kim,et al.  Development of high speed rotating arc sensor and seam tracking controller for welding robots , 2001, ISIE 2001. 2001 IEEE International Symposium on Industrial Electronics Proceedings (Cat. No.01TH8570).

[3]  Zhengqiang Zhu,et al.  A vision-based algorithm for seam detection in a PAW process for large-diameter stainless steel pipes , 2005 .

[4]  Lin Tao,et al.  Light intensity analysis of a passive visual sensing system in GTAW , 2005 .

[5]  Tao Lin,et al.  Robot welding seam tracking method based on passive vision for thin plate closed-gap butt welding , 2010 .

[6]  De Xu,et al.  Visual seam tracking system for butt weld of thin plate , 2010 .

[7]  Suck-Joo Na,et al.  A Study on Arc Sensor Algorithm for Weld Seam Tracking in Gas Metal Arc Welding of Butt Joints , 1991 .

[8]  Kang-Yul Bae,et al.  An optical sensing system for seam tracking and weld pool control in gas metal arc welding of steel pipe , 2002 .

[9]  T. Qiu,et al.  Intelligent technologies for robotic welding , 2004 .

[10]  Shan-Ben Chen,et al.  Autonomous Acquisition of Seam Coordinates for Arc Welding Robot Based on Visual Servoing , 2006, J. Intell. Robotic Syst..

[11]  Hyungsuck Cho,et al.  A robust method for vision-based seam tracking in robotic arc welding , 1995, Proceedings of Tenth International Symposium on Intelligent Control.

[12]  Tao Lin,et al.  Real-Time Seam Tracking Technology of Welding Robot with Visual Sensing , 2010, J. Intell. Robotic Syst..

[13]  Shanben Chen,et al.  Visual sensing and penetration control in aluminum alloy pulsed GTA welding , 2009 .

[14]  S. Na,et al.  Mathematical modelling of rotational arc sensor in GMAW and its applications to seam tracking and endpoint detection , 2006 .

[15]  Hsing-Chia Kuo,et al.  An image tracking system for welded seams using fuzzy logic , 2002 .

[16]  Hyeong-Soon Moon,et al.  Automatic seam tracking in pipeline welding with narrow groove , 2009 .

[17]  XiaoQi Chen,et al.  Laser visual sensing for seam tracking in robotic arc welding of titanium alloys , 2005 .

[18]  Xinhua Tang,et al.  A visual seam tracking system for robotic arc welding , 2008 .

[19]  Tao Lin,et al.  Three-dimensional weld seam tracking for robotic welding by composite sensing technology , 2011, Ind. Robot.