By viewing the topside of a weld pool, a skilled operator can estimate the weld joint penetration. The weld pool shape or the solidified bead shape is crucial for weld quality. Automatic control of pulsed GTAW with wire filler is achieved by recording the image of the weld pool with an optical sensing method and then calculating shape parameters with an image processing algorithm. Three-dimensional shape parameters of the weld pool were determined that uniquely and accurately describe various weld pool shapes. Two-dimensional shape parameters were extracted from a two-dimensional image processing algorithm. Finally, a shape from shading (SFS) algorithm on a single image was used to recover the surface height from a single weld pool image. The extracted three-dimensional parameters for the weld pool surface were verified and used for double-sided shape control.

1.
Agapakis, J. E., and Bolstad, J., 1991, “Vision Sensing and Processing System for Monitoring and Control of Welding and Other High Luminosity Processes,” International Robots & Vision Automation Conference, pp. 23–29.
2.
Nakata
,
S.
,
Huang
,
J.
, and
Tsuruha
,
Y.
, 1988, “Visual Sensing System for In-Process Control of Arc Welding Process,” Welding International, 67, pp. 1086–1090.
3.
Kovacevic
,
R.
, and
Zhang
,
Y. M.
,
1996
. “
Sensing Free Surface of Arc Weld Pool Using Specular Reflection: Principle and Analysis
,”
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture
,
210
, pp.
553
564
.
4.
Pietrzak
,
K. A.
, and
Packer
,
S. M.
,
1994
, “
Vision-Based Weld Pool Width Control
,”
ASME J. Eng. Ind.
,
116
, pp.
86
92
.
5.
Richardson
,
R. W.
, and
Gutow
,
D. A.
,
1984
, “
Coaxial Arc Weld Pool Viewing for Process Monitoring and Control
,”
Weld. J. (Miami)
,
63
, pp.
43
50
.
6.
Brzakovic
,
D.
, and
Khani
,
D. T.
,
1991
. “
Weld Pool Edge Detection for Automated Control of Welding
,”
IEEE Trans. Rob. Autom.
,
7
, pp.
397
403
.
7.
Lou
,
Y. J.
,
Chen
,
S. B.
, and
Wu
,
L.
, 1999, “Monitoring of Weld Joint Penetration Based on Sensing Double-sided Vision Images of Weld Pool,” Journal of Harbin Institute of Technology, 6, pp. 26–31.
8.
Zhang
,
Y. M.
, and
Kovacevic
,
R.
,
1997
, “
Real-time Sensing of Sag Geometry During GTA Welding
,”
ASME J. Manuf. Sci. Eng.
,
119
, pp.
151
160
.
9.
Rokhlin
,
S. I.
, and
Guu
,
A. C.
,
1993
, “
A Study of Arc Force, Pool Depression, and Weld Penetration during Gas Tungsten Arc Welding
,”
Weld. J. (Miami)
,
72
, pp.
381s–390s
381s–390s
.
10.
Lin
,
M. L.
, and
Eagar
,
T. M.
,
1985
, “
Influence of Arc Pressure on Weld Pool Geometry
,”
Weld. J. (Miami)
,
64
, pp.
163s–169s
163s–169s
.
11.
Chen
,
S. B.
,
Wu
,
L.
,
Wang
,
Q. L.
, and
Liu
,
Y. C.
,
1997
, “
Self-learning Fuzzy Neural Network and Computer Vision for Control of Pulsed GTAW
,”
Weld. J. (Miami)
,
76
, pp.
201s–209s
201s–209s
.
12.
Kovacevic
,
R.
,
Zhang
,
Y. M.
, and
Li
,
L.
,
1996
, “
Monitoring of Weld Penetration Based on Weld Pool Geometrical Appearance
,”
Weld. J. (Miami)
,
75
, pp.
317s–328s
317s–328s
.
13.
Chen
,
S. B.
,
Zhao
,
D. B.
,
Wu
,
L.
, and
Lou
,
Y. J.
,
2000
, “
Intelligent Methodology for Sensing, Modeling and Control of Pulsed GTAW. Part II-Butt Welding
,”
Weld. J. (Miami)
,
79
, pp.
164s–174s
164s–174s
.
14.
Chen
,
S. B.
,
Lou
,
Y. J.
,
Wu
,
L.
, and
Zhao
,
D. B.
,
2000
, “
Intelligent Methodology for Sensing, Modeling and Control of Pulsed GTAW. Part I-Bead-on-plate Welding
,”
Weld. J. (Miami)
,
79
, pp.
151s–163s
151s–163s
.
15.
Zhang
,
Y. M.
,
Li
,
L.
, and
Kovacevic
,
R.
,
1997
, “
Dynamic Estimation of Full Penetration Using Geometry of Adjacent Weld Pools
,”
ASME J. Manuf. Sci. Eng.
,
119
, pp.
631
643
.
16.
Zhao
,
D. B.
,
Chen
,
S. B.
,
Wu
,
L.
,
Dai
,
M.
, and
Chen
,
Q.
,
2001
, “
Intelligent Control for the Double-sided Shape of the Weld Pool in Pulsed GTAW with Wire Filler
,”
Weld. J. (Miami)
,
80
, pp.
253s–260s
253s–260s
.
17.
Horn
,
B. K. P.
, and
Brooks
,
M. J.
,
1986
. “
The Variational Approach to Shape from Shading
,”
Comput. Vis. Graph. Image Process.
,
33
, pp.
174
208
18.
Horn
,
B. K. P.
,
1990
. “
Height and Gradient from Shading
,”
Int. J. Comput. Vis.
,
5
, pp.
37
75
.
19.
Lee
,
K. M.
, and
Kuo
,
C. J.
,
1993
, “
Surface Reconstruction from Photometric Stereo Images
,”
J. Opt. Soc. Am.
,
10
, pp.
855
868
.
20.
Lee
,
K. M.
, and
Kuo
,
C. J.
,
1997
, “
Shape from Shading with a Generalized Reflectance Map Model
,”
Comput. Vis. Image Underst.
,
67
, pp.
143
160
.
21.
Oren
,
M.
, and
Nayar
,
S. K.
,
1995
, “
Generalization of the Lambertian Model and Implication for Machine Vision
,”
Int. J. Comput. Vis.
,
14
, pp.
227
251
.
22.
Zheng
,
Q.
, and
Chellappa
,
R.
,
1991
, “
Estimation of Illuminant Direction, Albedo, and Shape from Shading
,”
IEEE Trans. Pattern Anal. Mach. Intell.
,
13
, pp.
680
702
.
You do not currently have access to this content.