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Welding Research and Development Lab
Applied Welding Technology
Weld joint penetration control based
on geometrical appearance of weld pool
Topic: Precise monitoring and control of weld joint penetration status
Difficulty: Invisibility of weld joint penetration
Approach: Emulation of human operator inference using neurofuzzy model and
geometry of weld pool
Tools: Neurofuzzy modeling, high speed image processing, predictive and robust
control algorithms
Sponsors: NSF, Navy Joining Center, Army Aviation Systems Command, Allison
Engine Company
Control System
Publications:
- Y. M. Zhang and L. Li, "Interval model based robust control of weld joint penetration," ASME Journal of Manufacturing Science and Engineering, 121(3): 425-433, 1999 .
- Y. M. Zhang, R. Kovacevic, "Neurofuzzy model based control of weld fusion zone geometry," Accepted for publication, October 28, 1997, IEEE Transactions on Fuzzy Systems, 6(3):389-401, 1998.
- Y. M. Zhang, L. Li, and R. Kovacevic, "Dynamic estimation of full penetration using geometry of adjacent weld pools," ASME Journal of Manufacturing Science and Engineering, 119(4): pp. 631-643, 1997.
- R. Kovacevic, Y. M. Zhang, "Neurofuzzy model-based weld fusion state estimation," IEEE Control Systems, 17(2): 30-42, 1997.
- R. Kovacevic, Y. M. Zhang, and L. Li, "Monitoring of weld penetration based on weld pool geometrical appearance," Welding Journal, 75(10): 317s-329s, 1996.
- Y. M. Zhang, R. Kovacevic, and L. Li, "Characterization and real-time measurement of geometrical appearance of weld pool," International Journal of Machine Tool and Manufacturing, 36(7): 799-816, 1996.
- R. Kovacevic, Y. M. Zhang, and S. Ruan, "Sensing and control of weld pool geometry for automated GTA welding," ASME Journal of Engineering for Industry, 117(2): 210-222, 1995.
- R. Kovacevic and Y. M. Zhang, "Machine vision recognition of weld pool in GTAW," Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 208(B2): 141-152, 1995.
Weld sag geometry monitoring and control
Topic: Robust sensing and control of depression and geometry of weld sag
Difficulty: Strong arc intensity and sensing delay
Approach: Structured-light sensing of weld sag behind the pool
Tools: Robust image processing, adaptive long-range predictive control
Targeting Sponsors: Aerospace and space industries
Control System
Publications:
- Y. M. Zhang and R. Kovacevic, "Real-time sensing of sag geometry during GTA welding," ASME Journal of Manufacturing Science and Engineering, 119(2): 151-160, 1997.
- Y. M. Zhang, R. Kovacevic, and L. Li, "Adaptive control of full penetration GTA welding," IEEE Transactions on Control Systems Technology, 4(4): 394-403, 1996.
- Y. M. Zhang, R. Kovacevic, and L. Wu, "Dynamic analysis and identification of gas tungsten arc welding process for full penetration control," ASME Journal of Engineering for Industry, 118(1): 123-136, 1996.
- Y. M. Zhang, L. Wu, B. L. Walcott, and D. H. Chen, "Determining joint penetration in GTAW with vision sensing of weld-face geometry," Welding Journal, 72(10): 463s-469s, 1993.
Double-sided arc welding for deep penetration
Topic: Deep penetration for improving productivity, narrowing heat-affected zone, and reducing cost
Difficulty: Limited penetration capability associated with conventional arc welding processes
Approach: Concentrating welding arc by directing the current through the work and the second electrode
Sponsors: NSF, ONR SBIR, National Shipbuilding Research Program, Lincoln Electric, NASA Marshall Flight Center, Thermal Arc.
Publications:
- C. S. Wu, J. S. Sun, and Y. M. Zhang, “Numerical Simulation of Dynamic Development of Keyhole in Double-Sided Arc Welding,” Modelling and Simulation in Materials Science and Engineering, 12(3): 423-442, 2004.
- Y. M. Zhang, S. B. Zhang, and M. Jiang, "Sensing and control of double-sided arc welding process," ASME Journal of Manufacturing Science and Engineering, 124(3):695-701, 2002.
- Y. M. Zhang, S. B. Zhang, and M. Jiang, "Keyhole double-sided arc welding process," Welding Journal, 81(11): 248s-255s, 2002.
- Y. M. Zhang, C. Pan, and A. T. Male, “Welding of austenitic stainless steel using double-sided arc welding process,” Materials Science and Technology, 17(11): 1280-1284, 2001.
- Y. M. Zhang, C. X. Pan, and A. T. Male, "Improvement of microstructures and properties of 6061 aluminum alloy weldments using double-sided arc welding process," Metallurgical and Materials Transactions A, Vol. 31A(10): 2537-2543, 2000.
- Y. M. Zhang, S. B. Zhang, M. Jiang, and L. Wu, "Keyhole double-sided arc welding process," Journal of Materials Science & Technology, 17(1): 159-160, 2000.
- Y. M. Zhang, C. X. Pan, and A. T. Male, "Solidification behavior of Al-Mg aluminum alloy using double-sided arc welding process," Journal of Materials Science Letters, Vol. 19, pp. 831-833, 2000.
- Y. M. Zhang and S. B. Zhang. "Welding aluminum alloy 6061 with opposing dual torch GTAW process," Welding Journal, 78(6): 202s-206s, 1999.
- Y. M. Zhang and S. B. Zhang, "Double-sided arc welding increases weld joint penetration," Welding Journal, 77(6):57-61, 1998.
- Y. M. Zhang and S. B. Zhang, "Method of arc welding using dual serial opposed torches," U.S. Patent Application, S.N. 9,049,191.
Metal transfer control in gas metal
arc welding
Topic: Precise control of melted metal drop size and transfer frequency
Difficulty: Dependence of detaching and retaining forces on process parameters
Approach: Lowering peak current to prevent undesired droplet detachment, taking advantage of the downward momentum of oscillating droplet to guarantee the detachment of the droplet under lowered peak current, oscillating the droplet as an active control action
Features: Electrical (voltage) signal sensing, guaranteed precise control of drop size and transfer, lowered peak current for thin-sectioned material welding
Supporting Companies: Thermal Arc
Targeting Sponsors: NSF, automotive industry
System
Publications:
- Y. M. Zhang, Liguo E, and B. L. Walcott. "Robust control of pulsed gas metal arc welding," ASME Journal of Dynamic Systems, Measurement, and Control, 124(2): 281-289, 2002.
- Y. M. Zhang and P. J. Li, "Modified active control of metal transfer and pulsed GMAW of titanium," Welding Journal, 80(2): 54s-61s, 2001.
- Y.M. Zhang, Ligueo E, and R. Kovacevic, 1998. "Method of gas metal arc welding," U.S. Patent Application S.N. 9,045, 437.
- Y.M. Zhang and Ligueo E, 1998. "Method and system for gas metal arc welding," U.S. Patent Application S.N. 9,048,758.
- Y. M. Zhang,Liguo E., and R. Kovacevic, "Active metal transfer control by monitoring excited droplet oscillation," Accepted for Publication, Welding Journal, 77(9): 388s-395s, 1998.
Structured-light based adaptive
submerged arc
welding: seam tracking and process control
Process: A cylinder is lapped on a cast head and joined by submerged arc welding
Problems: Varied groove geometry and weld seam
Requirement: Specified root pass penetration and reinforcement, X-ray test (ASME)
Approach: Structured-light based 3D vision for sensing groove geometry and weld profile, first pass for root penetration control, second pass for reinforcement control
Adjusted parameters: wire speed, arc voltage, torch position
Tools: Robust high-speed image processing
Applications: Tank manufacturing and other metal fabricators
SAW Process Control For Propane Tank
Machine vision based high-speed inspection
systems
Problems: Human inspectors can not precisely measure the sizes of welds, and often fail to detect undercuts, craters, and other weld defects Requirement: Short inspection cycle, manufacturing environment Approach: High-speed machine vision based automated inspection Tools: High frame rate camera (up to 3,000 frames of images per second), high speed image processing, and pattern recognition
Sponsors: Central Manufacturing Company, Thompson Steel Pipe, Ford Motors, Motor Wheels
Applications: Replacement of human inspectors
Laser machining and welding
Topics: Quality monitoring/control in laser drilling and welding, productivity improvement of drilling and assembly process
Applications: Engine blades, cylindrical structures
Approach: Sensing of reflected plasma arc intensity during drilling, sensing of geometry of drilled holes, sensing of temperature fields
Tools: CCD camera, IR sensors, illumination laser, high speed image processing
Facilities: 2kW CO2 laser, computer-controlled X-Y-Z table, IR sensors, high frame rate camera.
Sponsors: NSF, Pratt&Whitney
Targeting Sponsors: Automotive industries
Monitoring of 3D surface of weld pool
Topic: Monitoring of 3D topography of liquid metal pool deformed by arc pressure and fluid flow
Requirement: Moving torch
Difficulty: Strong arc light, high temperature, mirror-like pool surface
Approach: Optical grid with frosted glass, high-shutter speed camera
Application: Welding processes observation
Sponsor: NSF
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| Image of Weld Pool Surface |
Processed Image |
Publications:
- R. Kovacevic, Y. M. Zhang, "Real-time image processing for monitoring
of free weld pool surface," ASME Journal of Manufacturing Science and Engineering,
119(2): 161-169, 1997.
- R. Kovacevic, and Y. M. Zhang, "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 Manufacturing, 210(6):
553-564, 1996.
Technical Specialties
Welding Processes; Monitoring of Weld Joint Penetration From Front; Real-Time Image Processing; Dynamic Modeling; Neural Networks Modeling and Control; Neurofuzzy Modeling and Control; Self-Tuning Control; Predictive Control; Real-Time Control Software; Systems Integration.
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