• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.565-568
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• 2002

Welding variables and conditions in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the characteristic equations of the power supply, wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated, seam tracking procedure using arc sensor was simulated with variable V-Groove geometries and weaving frequencies. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.43-46
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• 1999

It has been suggested that the motivation for automation of welding processes ncludes the replacement and extension of the functions of human operators. Among these types of the welding automation, SAW(Submerged Arc Welding) was prevalently used, because it is highly suited to a wide range of application, especially for the high speed welding. A Significant portion of the total manufacturing time for a pipe fabrication process is spent on the welding following primary machining and fit-up processes. To achieve the reliable weld bead appearance, the automatic seam tracking and adaptive control to fill the groove are urgently needed. This paper proposed the mechanical functions of multi-torches welding system, flux supply and recovery system in conjunction with the complex air pulsing method and various types of methodologies. It was shown that the multi-torches welding system revealed the high welding qualities for the circular and rectangular pipes. In conclusion, the multi-torches welding system developed will contribute the advanced welding technology, welding automation and increment of the market in these areas.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.2
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• pp.124-132
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• 2001

Autonomous of welding process in shipyard is ultimately necessary., since welding site is spatially enclosed by floors and girders, and therefore welding operators are exposed to hostile working conditions. To solve this problem, a welding robot that can navigate autonomously within the enclosure needs to be developed. To achieve the welding ra나, the robotic welding systems needs a sensor system for the recognition of the working environments and the weld seam tracking, and a specially designed environment recognition strategy. In this paper, a three-dimensional laser vision system is developed based on the optical triangulation technology in order to provide robots with work environmental map. At the same time a strategy for environment recognition for welding mobile robot is proposed in order to recognize the work environment efficiently. The design of the sensor system, the algorithm for sensing the structured environment, and the recognition strategy and tactics for sensing the work environment are described and dis-cussed in detail.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.94.1-94
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• 2001

Arc sensor gives important groove information during welding. Automatic seam tracking control system with arc sensor has significant characteristics such that bead formation is given as decentralization of penetration and formation of concave bead profile and that a turning point of transverse weaving with constant arc length control is decided whether or not torch height reaches to a specified setting level. Furthermore, the rotating action of the arc prevents hanging of weld bead and forms flat bead surface under high speed welding condition. The variation of groove and deposition area can be detected from the trace of weaving. The area and width of weaving trace has close correlation with the area of groove and deposition. In this paper, main object of this system is to realize an adaptive microprocessor based controller ...

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.301-302
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• 2006

In this paper, the possibilities of the Infra-red sensor in sensing and control of the bead geometry in the automated welding process are presented. Infra-red sensor is a well-known method to deal with the problems with a high degree of fuzziness so that the sensor is employed to build the relationship between process variables and the quality characteristic the proposed above respectively. Based on several neural networks, the mathematical models are derived from extensive experiments with different welding parameters and complex geometrical features. The developed system enables to select the optimal welding parameters and control the desired weld dimensions during arc welding process.

• Journal of Welding and Joining
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• v.32 no.6
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• pp.35-40
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• 2014

The contact tip for gas metal arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. If the contact tip is damaged, it is a cause of lowering the welding productivity due to removal of welding defects and replacement of contact tip. In case of the use of a contact tip for a long time the arc is unstable because the processed hole in the contact tip center is larger, and the variation of aiming position of the welding wire causes a seam tracking error. In this study, gas metal arc welding experiments using contact tip of three different materials were performed. The contact tips with Cu-P, Cu-Cr, and Cu-ODS were used at the experiments, and the welding characteristics by each contact tip were evaluated. After welding contact tip appearance, welding spatter adhesion amount of the nozzle, and weld bead appearance were evaluated. The welding current and welding voltage were measured to verify arc stability during arc welding.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.776-787
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• 2002

Automation of welding process in shipyards is ultimately necessary, since the welding site is spatially enclosed by floors and girders, and therefore welding operators are exposed to hostile working conditions. To solve this problem, a welding mobile robot that can navigate autonomously within the enclosure has been developed. To achieve the welding task in the closed space, the robotic welding system needs a sensor system for the working environment recognition and the weld seam tracking, and a specially designed environment recognition strategy. In this paper, a three-dimensional laser vision system is developed based on the optical triangulation technology in order to provide robots with 3D work environmental map. Using this sensor system, a spatial filter based on neural network technology is designed for extracting the center of laser stripe, and evaluated in various situations. An environment modeling algorithm structure is proposed and tested, which is composed of the laser scanning module for 3D voxel modeling and the plane reconstruction module for mobile robot localization. Finally, an environmental recognition strategy for welding mobile robot is developed in order to recognize the work environments efficiently. The design of the sensor system, the algorithm for sensing the partially structured environment with plane segments, and the recognition strategy and tactics for sensing the work environment are described and discussed with a series of experiments in detail.