• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.11
• /
• pp.1697-1705
• /
• 2022

The safety of marine construction workers and marine pollution problems are occurring due to large-scale offshore construction. In particular, underwater construction work in the sea has a higher risk than other work, so it is necessary to apply an unmanned alternative system that considers the safety of the workers. In this paper, the ROV system for offshore construction has been developed for underwater unmanned work. A monitoring system was developed for position control through the control of underwater propellants, pneumatic gripper, and monitoring of underwater work. As a result of the performance evaluation, the underwater movement speed of the ROV was evaluated to be 0.89 m/s, and it was confirmed that the maximum load of the pneumatic gripper was 80 kg. In addition, the network bandwidth required for underwater ROV control and underwater video streaming was evaluated to be more than 300Mbps, wired communication at 92.7 ~ 95.0Mbit/s at 205m, and wireless communication at 78.3 ~ 84.8Mbit/s.

• ICROS
• /
• v.15 no.1
• /
• pp.22-28
• /
• 2009

병렬기구는 조립, 포장, 기계가공, 크레인, 수중공학, 항공 및 해양구조, 비행 및 3D 시뮬레이션, 위성 접시안테나 위치제어, 망원경 자세제어, 그리고 정형외과 수술 등 여러 분야에 사용되고 있다.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.3
• /
• pp.233-242
• /
• 2023

In this paper, the effect of mass injection on the control of tip vortex cavitation was studied experimentally. A mass injection system for a 3D hydrofoil was designed to control the location of injection as well as the injection rate. A series of cavitation tests were carried out in a cavitation tunnel for different injection locations and rates. The cavitation behaviour was observed using a high-speed camera and the corresponding noise was measured using a hydrophone installed in the observation window. The results showed that the tip vortex cavitation was suppressed under certain conditions and the noise was reduced in some frequency bands. It was also found that there is a location where the effect of mass injection could be maximized and hence the noise reduction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.135-140
• /
• 2004

In this paper, we study the posture control of an underwater vehicle with nonholonomic constraint. Generally, systems with nonholnomic constraints cannot be stabilized to an equilibrium points by smooth state feedback control. Therefore, we proposed a control strategy for posture control of the underwater vehicle using backstepping control. The proposed control scheme is applied to the posture control of an underwater vehicle and verified the effectiveness of control strategy by numerical simulation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.11a
• /
• pp.41-46
• /
• 2004

In this paper, we study the stabilization control if an underwater vehicle from its initial posture to its desired one. We assume tint the underwater vehicle has velocity constraint, i.e. it has no velocity component for some direction. Our approach is based on the nonholonomic system which am derived from velocity constraints that cannot integrable. We proposed a control strategy for posture control of the underwater vehicle using multi-rate digital control. The proposed control scheme is applied to the berthing control if an underwater vehicle and verified the effectiveness if control strategy by numerical simulation.

• Journal of Navigation and Port Research
• /
• v.28 no.6
• /
• pp.469-474
• /
• 2004

In this paper, we study the posture control of an underwater vehicle with nonholonomic constraint. Generally, systems with nonholnomic constraints cannot be stabilized to an equilibrium points by smooth state feedback control. For the nonholonomic underwater vehicle system, we applied coordinate transformation to get multi-chained system We proposed non smooth feedback controller using backstepping method for stabilizing the multi chained form system Applying inverse input transformation to the non smooth feedback controller, we can get posture controller of the underwater vehicle with nonholonomic constraint. The proposed control scheme is applied to the posture control qf an underwater vehicle and verified the effectiveness of control strategy by numerical simulation.

• Smart Media Journal
• /
• v.11 no.9
• /
• pp.64-74
• /
• 2022

A number of studies related to underwater robots are being conducted to utilize marine resources. However, unlike ordinary drones, underwater robots have a problem that it is not easy to locate because the medium is water, not air. The monitoring and positioning program of underwater robots, an existing study for identifying underwater locations, has difficulty in locating and monitoring in small spaces because it aims to be utilized in large spaces. Therefore, in this paper, we propose a three-dimensional positioning program for continuous monitoring and command delivery in small spaces. The proposed program consists of a multi-dimensional positioning monitoring function and a ability to control the path of travel through a three-dimensional screen so that the depth of the underwater robot can be identified. Through the performance evaluation, a robot underwater could be monitored and verified from various angles with a 3D screen, and an error within the assumed range was verified as the difference between the set path and the actual position is within 6.44 m on average.

• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2017.11a
• /
• pp.131-132
• /
• 2017

본 논문에서는 수중 초음파 전송을 이용하여 해양 사고 발생 시 수중 실종자의 신원과 위치를 파악할 수 있는 재난 대응 시스템을 제안한다. 실종자 몸에 부착된 초음파 발생기에서 나온 신호를 해상에 배치된 다수의 하이드로폰 센서 노드에서 감지, 분석해 저전력 통신으로 선박 등에 설치된 중앙 제어시스템에 보내면 이를 분석해 실종자의 위치 등을 판별할 수 있어 수색 작업에 큰 도움이 될 것으로 기대된다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.7
• /
• pp.709-715
• /
• 2015

Underwater gliders do not typically have separate propellers for forward motion. They generate propulsive forces based on the difference between their buoyancy and gravity. They can control the volume from the buoyancy engine to adjust the propulsive force. In addition, the attitude of the underwater glider is controlled by a rubberless motion controller. The motion controller can change the mass center and moment of inertia of the inner moving mass. Owing to the change in these parameters, the attitude of the underwater glider is changed. In this study, we derive nonlinear, six degree of freedom (DOF) mathematical models for the motion controller and buoyancy engine. Using these equations, we perform dynamic simulations of the proposed underwater glider, and verify the suitability of the design and dynamic performances of the proposed underwater glider. We then perform the motion control simulation for the pitch and roll angle, and analyze the dynamic performance according to the pitch and roll angles.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.1
• /
• pp.95-100
• /
• 2021

This paper introduces model-based meta reinforcement learning as a control for the manipulator of an underwater construction robot. Model-based meta reinforcement learning updates the model fast using recent experience in a real application and transfers the model to model predictive control which computes control inputs of the manipulator to reach the target position. The simulation environment for model-based meta reinforcement learning is established using MuJoCo and Gazebo. The real environment of manipulator control for underwater construction robot is set to deal with model uncertainties.