• Journal of Welding and Joining
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• 제8권1호
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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.

• 대한원격탐사학회지
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• 제27권1호
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• pp.25-31
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• 2011

원형레일을 기반으로 하는 지상 SAR 시스템인 ArcSAR 시스템에서 간섭(interferometry)기법의 적용이 가능한 정밀한 지상 SAR 영상을 획득하기 위해서는 안테나 위치의 정밀한 제어가 요구된다. 본 연구에서는 자력 선형 스케일(Magnetic Linear Scale)을 이용하여 기존 ArcSAR 시스템에서의 안테나 위치 값의 정확도를 분석하였으며 자력 엔코더(Encoder) 값을 이용하여 안테나 위치를 정밀하게 제어할 수 있는 기술을 개발하였다. 기존의 ArcSAR 시스템의 제어 체계에서는 안테나 회전 각도에 대한 평균 RMS 오차가 $0.043^{\circ}$였으나, 본 기술을 통해 $0.006^{\circ}$로 감소시킬 수 있었다. 이는 3미터 길이의 arm을 기준으로 할 때, 안테나 위치 정확도에 대한 평균 RMS 오차가 2.262mm에서 0.324mm로 감소된 것에 해당한다. 본 기술을 통해 매우 정밀한 지상 SAR 영상자료의 획득이 가능하게 되었으며 향후 간섭기법의 적용을 통해 지반 및 대형 구조물의 미세변위에 대한 초정밀 모니터링에 활용될 수 있을 것으로 기대된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2100-2104
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• 2004

Amount of Electricity which product generator decide control valve at Turbine. Operating method of Control valve have two mode. First operating method is Partial Arc Admission, and second operating method is Full Arc Admission. Failure of Control Valve have on serious damage electricity lineage. In this Paper, We have investigated resonance that Control Valve spring casing.

• 대한전자공학회논문지TE
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• 제42권3호
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• pp.19-24
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• 2005

본 연구에서는 일반 주택이나 저전력의 전기를 사용하는 전기환경에서 발생하는 전기 화재의 원인이 되는 아크를 검출하고 부하 전류를 차단하여 화재를 방지할 수 있는 제어기를 설계하였다. 전기 화재를 방지하기 위해 전기가 발명된 이래로 많은 변천이 있어왔다. 휴즈에서 시작하여 일반 누설전류에서 동작하는 차단기를 거쳐 아크를 검출하고 부하전류를 제어할 수 있는 장치까지 개발되기에 이르렀다. 현재 발생하는 많은 전기 화재의 원인은 아크로 인해 발생하는 것으로 확인되었다. 본 연구를 통해서 일반 전기 환경에서 발생하는 전기 화재의 원인을 미연에 검출하여 인명피해는 물론이고 물질적인 피해를 방지할 수 있도록 하였으며, 본 연구를 계속적으로 확대하여 대전력 환경에서도 안정적으로 동작할 수 있는 제어기를 설계하고자 한다.

• 한국기계가공학회지
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• 제16권1호
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• pp.112-117
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• 2017

The arc, generated by Tungsten Inert Gas(TIG) welding, is stable and provides excellent quality of the weld. Since automation is difficult, a lot of work is performed by hand. In addition, to obtain the uniform weld quality is difficult when using a base metal having a nonuniform welding line, or when welding inside a pipe. Generally, TIG welding power has the characteristic of constant-current. The welding voltage is changed in proportion to the arc length. Hence, the automatic voltage control equipment should be applied at the TIG welding system. The automatic voltage control equipment has been designed using LabVIEW software. It consists of a manufactured voltage divider circuit, and jig for moving the torch. The voltage measurements and driving of the motor were performed through the algorithm implementation in LabVIEW. Welding was conducted while increasing the arc length. In this process, it was confirmed that the automatic voltage control equipment kept the arc length constant.

• Journal of Welding and Joining
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• 제16권6호
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• pp.7-16
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• 1998

• Journal of Welding and Joining
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• 제18권4호
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• pp.82-86
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• 2000

Gas metal arc welding(GMAW) is regarded as one of the best candidate for welding automation in industrial joining application. It is important to monitor the weld quality for the high performance weld automation. In GMAW, weld quality is closely related to arc stability especially. In this paper, arc light signal is measured and spectrum analyzed to the detect the variation of the weld quality. The FFT of the signal showed that the amplitude variance of FFT power spectrum was very large in poor weld process such as the decrease of weld bead width and height. The results show that it is possible to detect the weld defect position in weld process.

• 대한기계학회논문집A
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• 제20권9호
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• pp.2760-2769
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• 1996

The feedback control systems of welding process using visual information can improve weld qualities. However, it is very difficult to get the visual information of weld pool since the light intensity of welding arc is much stronger than that of the weld pool. To explore the possibility of extending the capability of automatic welding machines, a study of a closed loop controlled welding system consisted of a GTA welding machine, a vision system, a stepping motor system and a digital computer was undertaken. Particularly, in this system, a CCD camera with a long wavelength pass filter was used to get a better weld pool image. Subsequently, an image analysis technique has been developed to measure the weld pool width. Using this weld pool width measurement, a colsed loop control system adjusted welding speed to maintain a constant weld pool width.

• 한국지능시스템학회논문지
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• 제18권6호
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• pp.821-825
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• 2008

본 논문에서는 전기로에 투입되는 합금철의 중량을 보다 정밀하게 제어하기 위하여 Mamdani 타입의 퍼지 알고리듬을 적용하였다. 고안된 퍼지 시스템은 중량 오차 및 변화를 입력으로 하고 합금철 투입 바이브레이터의 진동의 크기를 출력으로 하며, programmable logic controller의 래더 프로그램으로 구현하여 현장에 적용하였다. 현장에 적용된 퍼지 제어 알고리듬은 기존의 온-오프 제어기에 비하여 전기로에 투입되는 합금철의 계량 정밀도를 높였을 뿐 아니라, 합금철 투입 시간도 크게 단축시켰다.

• 한국해양공학회지
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• 제25권6호
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• pp.1-8
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• 2011

This paper describes a new method for a digital gas metal arc welding (GMAW) system. The GMAW system is an arc welding process that incorporates the GMAW power source (PS-GMAW) with a wire feed unit (WFU). The PS-GMAW requires an electric power of constant voltage. A constant magnitude is maintained for the arc current by controlling the wire-feed speed of the WFU. A mathematical model is derived, and a self-tuning fuzzy proportional-integral-derivative (PID) controller is designed and applied to control the welding current. The electrode wire feeding mechanism with this controller is driven by a DC motor, which can compensate for both the molten part of the electrode and undesirable fluctuations in the arc length during the welding process. By accurately maintaining the output welding current and welding voltage at constant values during the welding process, excellent welding results can be obtained. Simulation and experimental results are shown to prove the effectiveness of the proposed controller.