• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.9-10
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• 2012

This paper presents an observer to measure the lengths of cylinders of an underwater robot for harbour construction using a pressure sensor. In harbour constructing, we place heavy armour stones weighing over 2~3 tons on the surface of the bank to protect it from storming wave. This work typically done by a diver is difficult and dangerous so that we have developed Stone Diver which is the underwater robot for harbour construction. The robot needs a position sensor to control the hydraulic cylinder. The position sensors mounted outside the cylinders cause poor durability in construction site where shock and dust usually occur. However, the pressure sensor mounted inside a waterproof box improves the durability. Based on the dynamic parameters and the pressures in the cylinder, the observer measures the cylinder's position. This paper presents the positional accuracy of the pressure based observer and the performance of the underwater robot to assemble the armour stones.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.865-871
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• 2012

This paper presents an observer to estimate the displacement of hydraulic cylinders of an underwater robot for harbour construction using a pressure sensor. In harbour constructing, we place heavy armour stones weighing over 2~3 tons on the surface of the bank to protect it from storming wave. This work typically done by a diver is difficult and dangerous so that we have developed Stone Diver which is the underwater robot for harbour construction. The robot needs a displacement sensors to control the position of hydraulic cylinders. The position sensors mounted outside the cylinders cause poor durability in construction site where shock and dust usually occur. However, the pressure sensor mounted inside a waterproof box improves the durability. Based on the dynamic parameters and the pressures in the cylinder, the observer estimates the cylinder's position. This paper presents the positional accuracy of the pressure based observer and the performance of the underwater robot to assemble the armour stones.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.316-318
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• 2014

등표는 등화 (燈火)를 사용한 항로표지 중에서 암초나 얕은 곳의 위치를 표시하는데 설치되는 시설물로 해난사고 예방을 위한 매우 중요한 안전시설물이다. 등표는 해상의 암초에 설치되는 현장여건상 수중조사시 사고 위험성이 매우 높아 담당자가 직접 현장조사 참여에는 한계가 있으며 설계용역사에서 조사한 자료를 중심으로 작성된 설계도서에 의존하여 공사가 시행되고 있는 실정이다. 이러한 단점을 극복하고 현장여건에 적합한 성공적인 등표 설치공사 추진으로 예산을 절감하였으며 이러한 공로를 인정받아 2013년~2014년 2년 연속 기획재정부 주관 예산절감 사례에 당선되었다.

• Journal of Navigation and Port Research
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• v.39 no.3
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• pp.253-260
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• 2015

There are many efforts to mechanize the process for underwater port construction due to the severe and adverse working environment. This paper presents an underwater construction robot to level rubbles on the seabed for port construction. The robot is composed of a blade and a multi-functional arm to flatten the rubble mound with respect to the reference level at uneven terrain and to dig and dump the rubbles. This research analyzes the kinematics of the blade and the multi-functional arm including track and swing motions with respect to a world coordinate assigned to a reference depth sensor. This analysis is conducted interfacing with the position and orientation sensors installed at the robot. A hydraulic control system is developed to control a track, a blade and a multi-functional arm for rubble leveling work. The experimental results of rubble leveling work conducted by the robot are presented in land and subsea. The working speed of the robot is eight times faster than that of a human diver, and the working quality is acceptable. The robot is expected to have much higher efficiency in deep water where a human diver is unable to work.

• Journal of Navigation and Port Research
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• v.33 no.5
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• pp.323-330
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• 2009

We have been developing an underwater robot for harbour construction using a parallel mechanism The robot is attached to the rope of a crane, which curries a large stone into the undersea The robot's yaw and pitch are controlled by hydraulic cylinders but its roll is uncontrollable. We mount propellers in both side of the robot to generate the roll motion This paper studies on the control for the roll motion of a underwater robot. A gyro-sensor is used to measure the angle in a roll motion We develop the dynamic model to describe the robot's roll motion by a second order non-linear system and identify the model parameters by recursive least square and adaptive identifier. PD control, recursive model based control and adaptive model based control are applied with the dynamic model which computes the control input to compensate disturbances. This paper introduces the underwater robot system and presents the simulated and experimental results of the proposed controller.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8889-8895
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• 2015

It is necessary to secure the underwater visibility in order to perform underwater works such as rubble mound leveling or inspection and management of underwater structures. In this study, turbidity data for typical port area in Korea were measured and analyzed according to the region. Underwater monitoring system including underwater camera and sonar system, which can be effectively attached to underwater equipment for various turbidity conditions, was also investigated.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1781-1786
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• 2003

This research develops a robot as the device which constructs underwater harbour. This construction is to build a breakwater, which is dangerous and difficult. The hydraulic parallel mechanism-typed robot is developed to mechanize the construction by operating of a stoneworker (or diver) through a joystick. The six-dof robot is able to carry 2-3 tons' heavy stone and put it on the surface of breakwater. This paper presents the mechanical design of a miniature robot, its control and application for the breakwater construction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.49-51
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• 2018

항로표지시설은 방파제 상치, 노출암, 수중암, 산지 정상 등 다양한 입지에 건설되었으며, 항로표지시설에 대한 정밀안전진단결과(침하, 경사, 전도, 활동, 파손, 균열, 박리, 마모, 침식, 세굴 등) 내구수명은 파랑 및 조류 등 해양환경에 직접적으로 노출된 경우 20년, 비교적 해양환경에 노출이 심하지 않은 경우 40년 정도로 조사되었다. 안전진단 결과 등급이 낮은 순으로 항로표지시설 개량공사 계획이 수립 되고 있으며, 입지 여건에 따른 철거 및 시공방법에 대한 다양한 사례를 조사하여 시공기술을 제시하였다.

• Explosives and Blasting
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• v.25 no.2
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• pp.71-78
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• 2007

In many cases of underwater blasting in South Korea, the special blasting is mainly used for deepening harbor, installing gas pipes, or well blasting to build a bridge. The procedure of well blasting is almost same with shaft blasting, but the difference is that water is filled in before blasting. In case of deepening blasting under water, the first step like drilling, arranging explosives, and wire connection is done on a barge, then the next step such as charging and tamping is accomplished under water by expert divers. Therefore, underwater blasting needs precise and exact plan before blasting. In this paper, authors would like to introduce a case of underwater blasting for deepening the Busan new port with emulsion explosives and non-electric detonators in order to get some of 8,500TEU out sized container vessels entered into the port and to make safe. Considering environment and vibration, the blasting was controlled to minimized the damage to the lighthouse nearby. It will be great help to many other blasting sites where emulsion explosives and non-electric detonators are used for underwater blasting through this case.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.163-170
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• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction of 9 new ports and renovation of the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built of steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions of structures and increased underwater construction period. For the purpose of cutting down the expense of government budget, it is necessary to extend the life cycle of the existing structures. Therefore, we developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction maintenance expenses and time for anti-corrosion work but also better protection. This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.