DOI QR코드

DOI QR Code

Study of Intelligent Vision Sensor for the Robotic Laser Welding

  • Kim, Chang-Hyun (Dept. of Electrical Engineering and Computer Science Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Choi, Tae-Yong (Dept. of Electrical Engineering and Computer Science Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Lee, Ju-Jang (Dept. of Electrical Engineering and Computer Science Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Suh, Jeong (Korea Institute of Machinery and Materials (KIMM)) ;
  • Park, Kyoung-Taik (Korea Institute of Machinery and Materials (KIMM)) ;
  • Kang, Hee-Shin (Korea Institute of Machinery and Materials (KIMM))
  • Received : 2019.03.16
  • Accepted : 2019.06.07
  • Published : 2019.07.31

Abstract

The intelligent sensory system is required to ensure the accurate welding performance. This paper describes the development of an intelligent vision sensor for the robotic laser welding. The sensor system includes a PC based vision camera and a stripe-type laser diode. A set of robust image processing algorithms are implemented. The laser-stripe sensor can measure the profile of the welding object and obtain the seam line. Moreover, the working distance of the sensor can be changed and other configuration is adjusted accordingly. The robot, the seam tracking system, and CW Nd:YAG laser are used for the laser welding robot system. The simple and efficient control scheme of the whole system is also presented. The profile measurement and the seam tracking experiments were carried out to validate the operation of the system.

Keywords

SOOOB6_2019_v22n4_447_f0001.png 이미지

Fig. 1 Developed welding profile sensor

SOOOB6_2019_v22n4_447_f0002.png 이미지

Fig. 2 Center of gravity (COG) with thresholding

SOOOB6_2019_v22n4_447_f0003.png 이미지

Fig. 3 Averaging window for smoothing

SOOOB6_2019_v22n4_447_f0004.png 이미지

Fig. 4 Averaging results with different window sizes

SOOOB6_2019_v22n4_447_f0005.png 이미지

Fig. 5 Seam detection of a butt joint

SOOOB6_2019_v22n4_447_f0006.png 이미지

Fig. 6 Three dimensional laser welding

SOOOB6_2019_v22n4_447_f0007.png 이미지

Fig. 7 Sensor guided laser welding robot system

SOOOB6_2019_v22n4_447_f0008.png 이미지

Fig. 8 Control architecture

SOOOB6_2019_v22n4_447_f0009.png 이미지

Fig. 9 Sensor guided control scheme

SOOOB6_2019_v22n4_447_f0010.png 이미지

Fig. 10 Profile measurement of the calibration block

SOOOB6_2019_v22n4_447_f0011.png 이미지

Fig. 11 Sample specimens and their profiles

SOOOB6_2019_v22n4_447_f0012.png 이미지

Fig. 12 Specimen with various gap widths

SOOOB6_2019_v22n4_447_f0013.png 이미지

Fig. 13 Gap measuremen

SOOOB6_2019_v22n4_447_f0014.png 이미지

Fig. 14 S-shaped seam line and its dimension

SOOOB6_2019_v22n4_447_f0015.png 이미지

Fig. 15 Seam tracking results

SOOOB6_2019_v22n4_447_f0016.png 이미지

Fig. 16 Still images of S-shaped seam tracking

References

  1. J. Forest and J. Salvi, "A review of laser scanning three-dimensional digitisers," Proc. IEEE Conf. on Intelligent Robots and Systems (IROS'02), pp. 73-78, Lausanne, Switzerland, October 2002.
  2. K. Haug and G. Pritschow, "Robust laser-stripe sensor for automated weld-seam-tracking in theshipbuilding industry," Proc. Conf. of the IEEE Industrial Electronics Society (IECON'98), pp. 1236-1241, Aachen, Ger- many, August 1998.
  3. Y.I. Abdel-Aziz and H.M. Karara, "Direct linear transformation from comparator coordinates into object space coordinates in close-range photogrammetry," Proc. the Symposium on Close-Range Photogrammetry, pp. 1-18, 1971.
  4. Z. Zhang, "A flexible new technique for camera calibration," IEEE Trans. Pattern Anal. Mach. Intell., Vol.22, No.11, pp. 1330-1334, 2000. https://doi.org/10.1109/34.888718
  5. J. Canny, "A computational approach to edge detection," IEEE Trans. Pattern Anal. Mach. Intell., Vol. 8, No. 6, pp. 679-698, 1986. https://doi.org/10.1109/TPAMI.1986.4767851
  6. M.W. Graaf, R.G.K.M. Aarts, J. Meijer, and J.B. Jonker, "Robot-sensor synchronization for real-time seam-tracking in robotic laser welding," Proc. WLT-Conf. on Lasers in Manufacturing, pp. 419-424, Munich, Germany, June 2005.
  7. L. Zhou, T. Lin and S.B. Chen, "Autonomous acquisition of seam coordinates for arc welding robot based on visual servoing," Journal of Intelligent and Robotic Systems, Vol. 47, No. 3, pp. 239-255, 2006. https://doi.org/10.1007/s10846-006-9078-9