• 한국해양공학회지
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• 제33권2호
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• pp.178-188
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• 2019

When burying underwater cables using robots, heading control is one of the key functions for the robots to improve task efficiency. This paper addresses the heading control issue for URI-T, an ROV for underwater construction tasks, including the burial and maintenance of cables or small diameter pipelines. Through modeling and identifying the heading motion of URI-T, the dynamic characteristics and input limitation are analyzed. Based on the identification results, a PD type controller with appropriate input treatment is designed for the heading control of URI-T. The performance of the heading controller was verified in water tank experiments. The field applicability of the proposed controller was also evaluated through the sea trial of URI-T at the East Sea, with a water depth of 500 m.

• 한국해양공학회지
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• 제34권5호
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• pp.361-370
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• 2020

We developed a heavy-duty work class ROV trencher named URI-T (Underwater robot it's trencher) that can conduct burial and maintenance tasks for underwater cables and small diameter pipelines. It requires various supporting systems, including a dynamic positioning (DP) vessel, launch and recovery system (LARS), A-frame, and winch in order to perform burial tasks because of its dimensions (6.5 m × 5.0 m × 4.5 m, 20 t) and the tough working environment. However, operating a DP vessel has disadvantages as it is expensive to rent and operate and it is difficult to adjust the working schedule for some domestic coast construction cases. In this paper, we propose a method using a barge instead of a DP vessel to avoid the above disadvantages. Although burying the cable and pipeline using a barge has lower working efficiency than a DP vessel, it can save construction expenses and does not require a large crew. The proposed method was applied over two months at the construction of the water supply in Yokji-do, and the results were verified.

• 센서학회지
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• 제32권3호
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• pp.199-206
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• 2023

This study presents a novel monitoring technique for underwater high-voltage direct current (HVDC) cables based on the Distributed Acoustic Sensor (DAS). The proposed technique utilizes vibration and acoustic signals generated on HVDC cables to monitor their condition and detect events such as earthquakes, shipments, tidal currents, and construction activities. To implement the monitoring system, a DAS based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) system was designed, fabricated, and validated for performance. For the HVDC cable monitoring experiments, a testbed was constructed on land, mimicking the cable burial method and protective equipment used underwater. Defined various scenarios that could cause cable damage and conducted experiments accordingly. The developed DAS system achieved a maximum measurement distance of 50 km, a distance measurement interval of 2 m, and a measurement repetition rate of 1 kHz. Extensive experiments conducted on HVDC cables and protective facilities demonstrated the practical potential of the DAS system for monitoring underwater and underground areas.

• 지구물리와물리탐사
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• 제27권1호
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• pp.57-68
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• 2024

온실가스 저감을 위하여 대규모의 단지를 건설할 수 있고 발전 효율성이 우수한 해상 풍력이 각광 받고 있다. 해상 풍력 단지에서 생산한 전력을 송전하기 위해서는 해저 전력 케이블이 필수적이며, 케이블의 모니터링 및 고장 지점 파악을 위하여 해저 케이블의 위치 또는 매설 심도 분석이 필요하다. 본 논문에서는 해저 전력 케이블을 탐지하기 위한 기술 및 연구에 대하여 소개하였으며, 탄성파/음향, 전자 탐사, 자력 탐사로 분류하여 조사하였다. 탄성파/음향은 주로 선박에 장비를 설치하여 해저 전력 케이블을 탐지하였으며, 전자 및 자력 탐사는 AUV, ROV와 같은 무인 잠수정에 장비를 설치하여 케이블을 탐지하였다. 본 논문을 활용한다면 해저 케이블 탐지 기술에 대한 기초자료로 사용될 수 있을 것으로 생각된다.