• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.4
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• pp.129-136
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• 2021

River facilities and port structures require a regular inspection and diagnosis due to obsolescence. Currently, most river facilities are undergoing indirect inspection and diagnosis by divers. The underwater inspections are not feasible due to safety issues of divers and restrictions on working hours and environment. To overcome these issues, it is intended to conduct inspections of river facilities using underwater drones. In this research, an underwater ROV (Remote Operated Vehicle) has been developed, which is a kind of drone with propellers. As a key device of this research, an injection device has been attached to the underwater drone to conduct an operation test, a stable operation test of an underwater drone, and a test of attached sensors. The river facility inspection can be carried out optimally using the hovering control of the drone and injection systems. With the developed ROV system, hovering test and injection test have been performed to verify the feasibility of this development.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1196-1202
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• 2009

In this paper, an estimator design of underwater environment changes is proposed by using observer techniques for ROV control system. The underwater environment changes are considered as an external disturbance term for ROV model and it is added into the input term of ROV model. To estimate the environment changes, a PI observer which does not effect the external disturbance input term is proposed. To verify the effectiveness of the proposed method, the step and the sinusoidal environment changes are considered in simulation. The proposed method will be applied to design the haptic controller for ROV in future.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.451-458
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• 2012

In this paper, the design study of a new convertible six d.o.f underwater robot which can be a ROV or AUV according to underwater work purpose is presented. A structure design about the ROV and the AUV and its design on the control system is presented. In case of the AUV, an analysis on thruster forces in accordance with operating speed has been performed. A sensor fusion board which can proceed various sensor signals to identify correct positions and speeds has been developed and a total control system including EKF(Extended Kalman Filter) has been designed and developed.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.463-471
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• 2020

Recently, various tries to apply ROV (Remotely Operated Vehicle) into underwater are being developed. However, due to underwater environment uniqueness, the additional problem must be taken into account when designing an ROV for the inspection of the underwater structure. This is because a GPS-based information method cannot be applied, and the obtainable image is also dependent on the turbidity. Also, it is necessary to be able to satisfy waterproof and operating speeds in consideration of most practical application environments. This paper describes the design results of the ROV system for underwater structure inspection considering the above problems. The designed system applied INS / DVL for location recognition and was configured to support 3D mapping and stereo camera-based image information using sonar depending on visibility. To satisfy the waterproof, a pressure vessel using a composite material was applied. And over-actuated system using eight thrusters to maintain a stable posture and operating speed was applied also. The designed system was verified by structural analysis and flow analysis also.

• Journal of Ocean Engineering and Technology
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• v.5 no.1
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• pp.45-54
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• 1991

본 논문은 케이블-ROV 시스템의 동적거동 규명을 위한 효과적인 해석방법에 대한 고찰이다. 해석방법에 대하여 일차적으로 연구하고 해석방법에 따른 소프트웨어를 개발하여 3차원 케이블-ROV 시스템 거동을 수치적으로 해석하였으며 같은 모델에 대한 거동을 실제 실험을 통하여 연구분석 하였다. 수치해석과 실험결과를 비교 검토하였고 여러가지 관련 문제점에 대해서도 연구하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.997-1002
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• 2008

This paper is mainly concerned with the development of a remotely operated vehicle for investigation of the coastal sea. For this, we have designed and constructed a vehicle entitled KMU-ROV(Korea Maritime University Remotely Operated Vehicle), for purpose of investigation mission under 50(m) of the sea surface. We have designed six independent waterproof actuators and the housing of the controller for underwater operation. For six degree-of-freedom motion, we have analyzed the dynamics of the KMU-ROV and have designed a new composition of six actuators including the driving system. For motion control, we have composed a concurrent velocity control algorithm for controlling the speed of all the actuating motors. The control system for the KMU-ROV is composed of a master DSP controller, DSP controller for the motor control and various sensors. We composed the PID control algorithm and a network system for controlling motors using the CAN communication. The performance of the KMU-ROV was presented by testing the developed control algorithm and control system under the water.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.300-311
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• 2019

An ROV trencher is a type of heavy-duty work class ROV equipped with high-pressure water jet tools for cutting into the sea floor and burying cables. This kind of trencher is mostly used for PLIB operations. This paper introduces the development of this kind of ROV trencher, which has a 698 kW power system, with a 250 kW hydraulic system and two 224 kW water jet systems. The project was launched in January 2014. After four years of design, manufacturing, and system integration, we carried out two sea trials near the Yeongilman port (about 20-30 m in depth) in Pohang to evaluate the system performance in November 2017 and August 2018. Through tests, we found that most of specifications were satisfied, including a maximum bury depth of 3 m, maximum bury speed of 2 km/h, and maximum forward speed of 1.54 m/s.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.39-47
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• 2020

This paper presents a control and operation system for a remotely operated vehicle (ROV). The ROV used in the study was equipped with a manipulator and is being developed for underwater exploration and autonomous underwater working. Precision position and attitude control ability is essential for underwater operation using a manipulator. For propulsion, the ROV is equipped with eight thrusters, the number of those are more than six degrees-of-freedom. Four of them are in charge of surge, sway, and yaw motion, and the other four are responsible for heave, roll, and pitch motion. Therefore, it is more efficient to integrate the management of the thrusters rather than control them individually. In this paper, a thrust allocation method for thruster management is presented, and the design of a feedback controller using sensor data is described. The software for the ROV operation consists of a robot operating system that can efficiently process data between multiple hardware platforms. Through experimental analysis, the validity of the control system performance was verified.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.41-47
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• 2009

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.7-14
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• 2006

This paper discusses the structural design and analysis of a 6,000 meters depth-rated capable deep-sea unmanned underwater vehicle (UUV) system. The UUV system is currently under development by Maritime and Ocean Engineering Research Institute(MOERI), Korea Ocean Research and Development Institute (KORDI). The UUV system is composed of three vehicles - a Remotely Operated Vehicle (ROV), an Autonomous Underwater Vehicle (AUV) and a Launcher - which include underwater equipment. The dry weight of the system exceeds 3 tons hence it is necessary to carry out the optimal design of structural system to ensure the minimum weight and sufficient space within the frame for the convenient use of the embedded equipments. In this paper, therefore, the structural design and analysis of the ROV and launcher frame system were carried out, using the optimizing process. The cylindrical pressure vessels for the ROV were designed to resist the extreme pressure of 600 bars, based on the finite element analysis. The collapse pressure for the cylindrical pressure vessels was also checked through a theoretical analysis.