• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2007년도 춘계학술대회
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• pp.133-141
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• 2007

Aerial working platform is recently used broadly in heavy industry and construction field and also the utilization of it is growing. However, the raise of critical incident caused by unskilled operator is increasing gradually. To reduce and prevent such incident, the training for operating is essential. It's not easy to cover the requirements for the training with real platform because of the high price of it, safety and weather condition. This paper proposes a simulator for the training based on virtual reality to give the training safely regardless to the weather condition and the simulator is deliverable in lower price than real one. The simulator proposed in this paper is available to be set according to the level of trainee managing the assessment level and be also applied for the design of general heavy equipment training simulator based.

• 대한안전경영과학회지
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• 제9권4호
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• pp.57-62
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• 2007

Aerial working platform is recently used broadly in heavy industry and construction field and also the utilization of it is growing. However, the raise of critical incident caused by unskilled operator is increased gradually. To reduce and prevent such incident, the training for operating is essential. It's not easy to cover the requirements for the training with real platform because of the high price of it, safety and weather condition. This paper proposes a simulator for the training based on virtual reality to give the training safely regardless to the weather condition and the simulator is deliverable in lower price than real one. The simulator proposed in this paper is available to be set according to the level of trainee's skill managing and be also applied for the design of general heavy equipment training simulator.

• Nuclear Engineering and Technology
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• 제50권4호
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• pp.613-618
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• 2018

We are developing a shared remote control mobile robot for aerial work in nuclear power plants (NPPs); a robot consists of a mobile platform, a telescopic mast, and a dual-arm slave with a working tool. It is used at a high location operating the manual operation mechanism of a fuel changer of a heavy water NPP. The robot system can cut/weld a pipe remotely in the case of an emergency or during the dismantling of the NPP. Owing to the challenging control mission considering limited human operator cognitive capability, some remote tasks require a shared control scheme, which demands systematic software design and integration. Therefore, we designed the architecture of the software systematically.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.296-303
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• 2002

Tribology, in other words, interacting surfaces in relative motion, is essential in life. The relative motion on surfaces may cause some problems with heat, vibration, noise, and so on. Unwanted vibrations by friction, which may arise during the operation of machines, are costly in terms of reduction of performance and service life. All these phenomena inolve stick-slip. The telescopic boom operations involves stick-slip oscillations like slideways. Unwanted stick-slip oscillations on telescopic boom operations cannot achieve smooth sliding and many developers of that machine makes a lot of effort to remove or reduce it. So this paper presents stick-slip oscillation with pressure of the hydraulic cylinder which drives booms, and attempts a theoretical approach for the numerical analysis for its stick-slip condition.

• Tribology and Lubricants
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• 제18권1호
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• pp.55-60
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• 2002

In many dynamic systems, there are unwanted oscillation which may arise the reduction of performance. Especially in low sliding speed condition, the stick-slip is an important issue because it because unstable motion as well as inaccurate position control in the system. Most previous works on the stick-slip are, however, only concerned with simple modeling under the condition of constant normal force. The normal force and the amount of hydraulic oil are variable with a cylinder stroke in the telescopic boom. This paper presents the pressure variations during stick-slip with the cylinder of telescope boom. Pressure variations by stick-slip has a similar pattern to that of single mass-spring model. The stick-slip is gradually decreased by means of increased flow rate.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.164-170
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• 2013

Quadrotor UAV (Unmanned Aerial Vehicle) is a flying robotic platform which has drawn lots of attention in the recent years. The attraction comes from the fact that it is able to perform agile VTOL (Vertical Take-Off Landing) and hovering functions. In addition, the efficient modular structure composed of four electric rotors makes its design easier compared to other single-rotor type helicopters. In many cases, a quadrotor often utilizes vision systems in order to obtain altitude control and navigation solution in hostile environments where GPS receivers are not working or deniable. For carrying out their successful missions, it is essential for flight control systems to have fast and stable control responses of heading angle outputs. This paper presents a Fuzzy Logic based lateral PI controller to stabilize and control the quadrotor vehicle equipped with vision systems. The advantage of using the fuzzy based PI controller lies in the fact that it could acquire a desired output response of a heading angle even in presence of disturbances and uncertainties. The performance comparison of the newly proposed Fuzzy-PI controller and the conventional PI controller was carried out with various simulation results.

• 대한공간정보학회지
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• 제23권2호
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• pp.39-48
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• 2015

최근, 무인항공촬영시스템(UAV, UAS, 또는 드론)은 자료취득을 위한 플랫폼 및 측정기기로서 사진측량의 응용분야, 특히 고밀도 측점자료(HDPC : High Density Point Clouds) 구성에 큰 관심이 모아지고 있다. 본 연구는 저가회전익 UAS 영상에 의한 시험대상지 지표면의 고밀도 측점자료를 구성하고 위치 정확도를 평가한 내용이다. 정확도 평가는 62개의 지상 검사점에 대한 Network RTK GNSS 측량 결과를 기준으로 UAS 기반 HDPC 모형의 좌표와 비교 검토하였다. 연구결과, 작업지역 정사영상 내, 검사점의 평면 및 수직 좌표성분의 평균제곱근오차(RMSE)는 각각 ${\sigma}_H={\pm}0.102m$ 및 ${\sigma}_V={\pm}0.209m$, 수직 좌표성분의 최대오차는 0.570m로서 '영상지도제작 작업규정'에 따른 축척 1:1000(출력 시, 평면위치오차 1m)의 정사영상모자익 제작이 가능하였다. 또한, 격자규격 $1m{\times}1m$, 수치지도축척 1:1000의 수치표고모델을 제작할 경우, '항공레이저측량 작업규정'제한 기준에는 약간 미흡하였지만, 소규모지역을 대상으로 회전익 무인항공촬영시스템에 의한 축척 1:1000~1:2500의 정사영상 및 수치표고모델 제작의 가능성을 확인할 수 있었다.