• 한국재난정보학회 논문집
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• 제17권3호
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• pp.556-567
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• 2021

연구목적: 본 연구에서는 무인이동체를 활용한 철도교량의 외관조사 점검을 보다 효율적이고 신뢰성 있게 점검을 위하여 무인이동체를 통해 촬영된 이미지를 바탕으로 다양한 방식의 딥러닝 기반 자동 손상 분석기술을 검토하였다. 연구방법: 취득된 이미지를 바탕으로 손상항목을 정의하고 학습데이터로 추출하여 딥러닝 분석 모델을 생성하였다. 그리고 철도교량의 외관 손상 중 균열, 콘크리트 박리·박락, 누수, 철근노출에 대한 손상 이미지를 학습한 모델을 적용하여 자동 손상 분석 결과로 테스트하였다. 연구결과: 분석 결과 평균 95%이상 검측 재현율을 도출하는 분석 기법을 검토할 수 있었다. 이와 같은 분석 기술은 기존 육안점검 결과 대비 보다 객관적이고 정밀한 손상 검측이 가능하다. 결론: 본 연구를 통해 개발된 기술을 통해 철도 유지관리 분야에서 무인이동체를 활용한 정기점검 시 자동손상분석을 통한 객관적인 결과도출과 기존 대비 소요시간, 비용저감이 가능할 것으로 기대된다.

• 대한건축학회논문집:구조계
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• 제35권2호
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• pp.3-11
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• 2019

The recent earthquake of Pohang (M5.4) and the Gyeongju earthquake (M5.8) suggested the possibility of a strong earthquake in Korea and reminded us that the Korea is no longer an earthquake-safe zone. In the disaster recovery stage in a disaster like an earthquake, the investigation of the damage situation and the safety assessment of the building serve to provide important information for the initial action such as establishment of the recovery strategy and rescue of the survivor. However, the research that depends on manpower can not cope with the difficulty of processing a large number of doses in a short time, and the expertise of the manpower must be taken into consideration, which may result in delayed initial action. In this study, we propose an rapid safety evaluation technique of building using unmanned aerial vehicle which evaluates the performance and safety of buildings by integrating conventional safety inspection method with unmanned aerial vehicle technology and developed evaluation method of each evaluation factor. In order to verify this, the buildings damaged by the earthquake in Pohang were checked and compared using this system. The results are consistent with the results of the existing emergency earthquake risk assessment. As a result, the possibility of checking the emergency safety using the unmanned aerial vehicle for the damaged structures in case of a large-scale disaster such as an earthquake was confirmed.

• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.262-268
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• 2012

In the recent research technical solutions have been studied to integrate renewable energy into unmanned aerial vehicles to use it as the main power source. As the weight of the aerial vehicle body is essential for its performance, we consider to use light-weight solar cell technology. Furthermore fuel cells are also integrated create a highly energy-efficient aerial robot. In this paper, construction concept and software design of the tilt-rotor aerial vehicle GAORI is introduced which uses solar cells and fuel cells as power source. The future work direction and prognosis are discussed.

• 산업경영시스템학회지
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• 제35권1호
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• pp.39-46
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• 2012

An unmanned aerial vehicle (UAV) is a powered aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or non-lethal payload. An UAV is very important weapon system and is currently being employed in many military missions (surveillance, reconnaissance, communication relay, targeting, strike, etc.) in the war. To accomplish UAV's missions, guarantee of survivability should be preceded. The main objective of this study is a local path planning to maximize survivability for UAV on the battlefield of dynamic threats (obstacles, surface-to-air missiles, radar etc.). A local path planning is capable of producing a new path in response to environmental changes. This study suggests a $Smart$ $A^*$ (Smart A-star) algorithm for local path planning. The local path planned by $Smart$ $A^*$ algorithm is compared with the results of existing algorithms ($A^*$ $Replanner$, $D^*$) and evaluated performance of $Smart$ $A^*$ algorithm. The result of suggested algorithm gives the better solutions when compared with existing algorithms.

• 산업공학
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• 제24권4호
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• pp.304-313
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• 2011

An Unmanned Aerial Vehicle(UAV) is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are currently employed in many military missions(surveillance, reconnaissance, communication relay, targeting, strike etc.) and a number of civilian applications(communication service, broadcast service, traffic control support, monitoring, measurement etc.). For accomplishing the UAV's missions, guarantee of survivability should be preceded. The main objective of this study is the path planning to maximize survivability for UAV based on 3-dimensional environment. A mathematical programming model is suggested by using MRPP(Most Reliable Path Problem) and solved by transforming MRPP into SPP(Shortest Path Problem). This study also suggests a $A^*PS$ algorithm based on 3-dimensional environment to UAV's path planning. According to comparison result of the suggested algorithm and SPP algorithms (Dijkstra, $A^*$ algorithm), the suggested algorithm gives better solution than SPP algorithms.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.313-318
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• 2010

The power plant system of a tilt rotor unmanned aerial vehicle (UAV) was verified by the Ironbird ground test, which considerably reduces cost and risk during the developmental stages. The function and performance of the engine, drive line, nacelle conversion, and rotor systems were evaluated using a building block test approach. The Ironbird test concept facilitates the discovery of potential faults in earlier stages of the testing period. As a result, the developmental testing period could effectively be shortened. The measured test data acquired through a ground control and data acquisition system exhibited satisfactory results which meet the developmental specifications of a tilt rotor UAV.

• 한국항공운항학회지
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• 제21권1호
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• pp.23-29
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• 2013

This paper presents a tracking filter of radar beacon system (RBS) for automatic takeoff and landing of an unmanned aerial vehicle. The proposed tracking filter is designed as the decoupled tracking filter to reduce the computational burden. Also, an adaptive estimation method of the measurement error covariance is proposed to provide an improved tracking performance compared to the conventional decoupled tracking filter whenever the accuracy of RBS observations is degraded. 100 times Monte Carlo runs performed to analyze the performance of the proposed tracking filter in case of normal operation and degraded operations, respectively. The simulation results show that the proposed tracking filter provides the improved tracking accuracy in comparison with the conventional decoupled tracking filter.

• 한국항공운항학회지
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• 제15권3호
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• pp.33-45
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• 2007

The collision avoidance maneuver flight simulation for tilt rotor unmanned aerial vehicle was performed by time-accurate numerical integration method based on wind tunnel test data. Five representative collision avoidance maneuvers were simulated under constraints of aerodynamic stall, propulsion power, structural load, and control actuator capability. The collision avoidance performances of the maneuvers were compared by the computed collision avoidance times. The sensitivities of initial flight speed and collision zone shape on the collision avoidance time were investigated. From these results, it was found that the moderate pull-up turn maneuver defined using moderate pitch and maximum roll controls within simulation constraints is the most robust and efficient collision avoidance maneuver under the various flight speeds and collision object shapes in the tilt rotor UAV applications.

• 대한안전경영과학회지
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• 제13권2호
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• pp.103-113
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• 2011

This research is to select a path planning algorithm to maximize survivability for Unmanned Aerial Vehicle(UAV). An UAV is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are currently employed in many military missions(surveillance, reconnaissance, communication relay, targeting, strike etc.) and a number of civilian applications(communication service, broadcast service, traffic control support, monitoring, measurement etc.). In this research, a mathematical programming model is suggested by using MRPP(Most Reliable Path Problem) and verified by using ILOG CPLEX. A path planning algorithm for UAV is selected by comparing of SPP(Shortest Path Problem) algorithms which transfer MRPP into SPP.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.226-230
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• 2010

본 논문에서는 배터리와 전기모터 방식의 추진장치를 사용하는 소형무인항공기의 비행성능을 분석한다. 비행시험을 통해 얻은 데이터로부터 공력특성을 예측하고, 이를 활용하여 비행성능을 예측한다. 최대 항속시간을 얻을 수 있는 적정 비행속도를 제시하고, 비행속도에 따른 항속시간 및 항속거리를 예측한다.