• Journal of Welding and Joining
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• v.14 no.6
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• pp.131-139
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• 1996

The response of the arc sensor using the welding current and/or welding voltage as its outputs has been obtained by the analysis and/or experiments of the static characteristics of arc sensor. But in order to improve the reliability of arc sensor, it is necessary to know its dynamic characteristics. So in this paper, it is presented the dynamic model of arc sensor including the power source, arc voltage, electrode burnoff rate, and wire feed rate. A numerical simulation of the dynamic model of arc sensor was implemented, computing the welding current with input of CTWD. The results of computer simulations and experiments of $CO_2$arc welding showed that a linear relationship between weaving center - weld line distance and current area difference was established. Additionally, a real-time weld seam tracking system interfaced with industrial welding robot was constructed, the result of the weld seam tracking experiment for weld line with an initial offset error of 5$^{\circ}$was good.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.321-322
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• 2016

본 논문에서는 수배전반에서 부하 설비 또는 외부의 영향을 확인할 수 있는 장치 및 보호설비가 설치되어 있으나 자체 사고를 신속히 검출하고 판단할 수 있는 기술의 확보를 위하여 해상도가 낮은 저가의 열화상 센서에 고속 DSP(Digital Signal Process)를 사용하여 영상 처리 기법인 이차원 보간법 기술을 이용하여 아크플래시에 의해 발생되는 열 특성을 검출하고 검출된 데이터를 전송하여 전기화재사고를 미연에 방지할 수 있는 장치 개발을 위한 기초 특성 연구를 수행하였다.

• Journal of Welding and Joining
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• v.16 no.3
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• pp.85-94
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• 1998

Welding fabrication invariantly involves three district sequential steps: preparation, actual process execution and post-weld inspection. One of the major problems in automating these steps and developing autonomous welding system, is the lack of proper sensing strategies. Conventionally, machine vision is used in robotic arc welding only for the correction of pre-taught welding paths in single pass. In this paper, developed vision processing techniques are detailed, and their application in welding fabrication is covered. The software for joint tracking system is finally proposed.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.133-136
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• 1997

• Proceedings of the KWS Conference
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• 1997.10a
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• pp.253-256
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• 1997

• Journal of Welding and Joining
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• v.16 no.5
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• pp.119-133
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• 1998

To implement full automation in pipe welding, it si most important to develop special sensors and their related systems which act like human operator when detecting irregular groove conditions. In this study, an automatic pipe Gas Metal Arc Welding (GMAW) system was proposed to full control pipe welding procedure with intelligent sensor systems. A five-axes manipulator was proposed for welding torch to automatically access to exact welding position when pipe size and welding angle were given. Pool status and torch position were measured by using a weld-pool image monitoring and processing technique in root-pass welding for weld seam tracking and weld pool control. To overcome the intensive arc light, pool image was captured at the instance of short circuit of welding power loop. Captured image was processed to determine weld pool shape. For weld seam tracking, the relative distance of a torch position from the pool center was calculated in the extracted pool shape to move torch just onto the groove center. To control penetration of root pas, gap was calculated in the extracted pool image, and then weld conditions were controlled for obtaining appropriate penetration. welding speed was determined with a fuzzy logic, and welding current and voltage were determined from a data base to correspond to the gap. For automatic fill-pass welding, the function of human operator of real time weld seam control can be substituted by a sensor system. In this study, an arc sensor system was proposed based on a fuzzy control logic. Using the proposed automatic system, root-pass welding of pipe which had gap variation was assured to be appropriately controlled in welding conditions and in torch position by showing sound welding result and good seam tracking capability. Fill-pass welding by the proposed system also showed very successful result by tracking along the offset welding line without any control of human operator.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.700-705
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• 2001

The paper presents a seam tracking controller of high speed rotating arc sensor developed by microprocessor based system. The seam tracking algorithm is based on the average current value at each interval region of four phase points on one rotating cycle. To remove the noise effect for the measured current, the area during one rotating cycle is separated into four regions of front, rear, left and right. The average values at each region are calculated, using the regional current values and a low pass filter incorporating the moving average and exponential smoothing methods is adopted.

• Journal of Welding and Joining
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• v.8 no.1
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• pp.23-30
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• 1990

The robotic welding has been adapted positively in many welding shops forthe purpose of improving the welding efficiency and liberating operators from the severe working atmosphere. But for a large-size structure with thick plates like ship-building and every kind of plants manufacturing, the application of the arc welding robots is not established yet. The reason is assumed that the conventional arc welding robots are not adaptive for multi-pass welding of thick plates whose grooves are not so accurate. As one solution to this problem, a guidance system which uses the welding arc itself as a sensor is largely used. In this study the velocity controller which changes the tip to workpiece distance for regulating the weld proposed. The proportional and integral gain of velocity controller were determined by using the computer simulation of the control system, and the simulation results compared with the experimental ones. It was revealed that the developed control system using the arc sensor principle has a good capability of tracking the weld joint, although some more studies will be needed to refine the model of arc current.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.132-140
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• 2000

Plasma arc cutting is one of the most widely used processes in metal cutting fields and is a process that produces parted metal plates by cutting them with an arc plasma established between the electrode tip and the plate(workpiece). When the tip-to-workpiece distance varies during cutting, the cut quality, for example the kerf width, is deteriorated by the change of plasma arc. The variations of tip-to-workpiece distance are due to the different factors such as inaccuracies in setting the torch or workpiece, thermal distortions during cutting, and uneven surface of workpiece. The control to keep the tip-to-workpiece distance constant is thus indispensable to improve the flexibility of automatic plasma arc cutting system applications. In this study, an arc sensor which utilizes the electrical signal obtained from the plasma arc itself was developed. The arc sensor has an advantage that no particular sensing device is necessary and real-time sensing of the tip-to-workpiece distance is possible directly under the plasma arc. The relationship between plasma arc voltage and tip-to-workpiece distance was determined through the repeated experimental results. The model was used for developing an automatic tip-to-workpiece distance control system of plasma arc cutting. It could be shown that the proposed system has a successful capability of tip-to-workpiece distance control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.349-353
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• 1992

로봇 경로프로그래밍 작업의 단순화는 산업용 로봇응용분야중 경로가 복잡할 경우, 예를 들어 연삭, 디버링, 폴리싱등 의 가공분야 그리고 아크용접같은 작업에서, 더욱 절실한 문제가 되고있다. 기존 로봇 프로그래밍 방식은 죠이스틱 또는 티칭 유니트, 오프라인 그리고 메스터-슬레이브 방식으로 구분될 수 있는데 각각 많은 프로그래밍 시간소요, 현장성부족 그리고 적용 로봇에의 한계를 문제점으로 들 수 있다. 여기서는 6축 수직 다관절 로봇의 손목부위에 6자 유도의 F/T 센서를 부착하여 작업자가 직접 로봇의 엔드 이펙트를 잡고 원하는 경로를 따라가는 동안 경로가 자동 프로 그래밍되는 알고리즘을 실험 결과와 함께 제시하고 있다.