• Geotechnical Engineering
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• v.34 no.1
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• pp.47-56
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• 2018

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

• 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 Ocean Engineering and Technology
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• v.29 no.5
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• pp.380-385
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• 2015

In the development of an underwater construction robot, the reliability of the operating system is the most important issue because of its huge maintenance cost, especially in a deep sea application. In this paper, we propose a new redundant architectural design for the hydraulic control system of an underwater construction robot. The proposed architecture consists of dual independent modular redundancy management systems linked with a commercial profibus network. A cold standby redundancy management system consisting of a preprocessing switch circuit is applied to the signal network, and a hot standby redundancy management system is adapted to utilize two main controllers.

• The Magazine of the IEIE
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• v.38 no.7
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• pp.30-36
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• 2011

최근 들어 녹색 성장과 해양 개발에 맞는 다양한 목적의 해양 구조물이 계획 또는 시공되고 있으며, 대형 해양 구조물에 대한 수요를 바탕으로 해양 구조물이 점차적으로 대수심 조건으로 옮겨가고 있는 추세이다. 이에 따라 미래 시장 예측을 통한 해양 구조물 수요 변화에 대해 미리 대처하고 미래해양구조물 니즈에 적극적으로 부합할 수 있는 방향으로 해양구조물 시공장비, 특히 수중로봇의 연구개발이 이루어져야 한다. 이 논문에서는 미래 해양구조물에 대한 개발 동향과 함께, 이에 따라 필요한 수중시공로봇의 역할과 기존의 개발 현황, 그리고 최근 기획사업을 통해 도출된 향후 연구개발 방향에 대한 분석내용을 소개하고자 한다.

• 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 Korea Information Processing Society Conference
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• 2017.04a
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• pp.685-687
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• 2017

최근 공중, 지상에 대해 무인 시스템이 빠른 속도로 발전하고 있다. 해양 분야에 대해서도 무인시스템이 발전함으로 인해 사람의 힘을 빌려 작업하기에는 많은 위험도와 각종 변수들에 의해 인명피해가 발생할 수 있는 건설, 케이블 매설, 해양 관측에 대해 무인 로봇을 통해 작업이 이루어지고 있다. 이러한 무인 시스템의 발전을 하드웨어는 빠르게 발전하여 컴포넌트 형태로 발전하였다. 이런 하드웨어의 발전에 맞춰 소프트웨어 컴포넌트 설계 방법을 제안하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.23-28
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• 2019

A track type underwater construction robot(URI-R) which can trench on seabed is being developed by Korea Institute of Ocean Science & Technology. During the underwater trenching work, the robot is exposed high intensive noise and vibration so the underwater localization signal may not be obtained properly by the acoustic tracking system. Therefore it is necessary to research about continuous localization even though the measured position signal comes in intermittently. In this paper, the experiments were carried out on land to simulated the underwater operating environment characteristics. To estimate its position, inertial navigation system and global navigation satellite system are used. The effects of the period variation while localizing is investigated by the experiments, and the application for URI-R is proposed.

• Journal of Navigation and Port Research
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• v.42 no.3
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• pp.237-244
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• 2018

When underwater rubble leveling work is carried out by a robot, real-time information on the topography around the robot is required for remote control. If the topographical information with respect to the current position of the robot is displayed as a 3D graphic image, it allows the operator to plan the working schedules and to avoid accidents like rollovers. Up until now, the topographical recognition was conducted by multi-beam sonars, which were only used to assess the quality before and after the work and could not be used to provide real-time information for remote control. This research measures the force delivered to the bucket which presses the mound to determine whether contact is made or not, and the contact position is calculated by reading the cylinder length. A variable bang-bang control algorithm is applied to control the heavy robot arms for the positioning of the bucket. The proposed method allows operators to easily recognize the terrain and intuitively plan the working schedules by showing relatively 3-D gratifications with respect to the robot body. In addition, the operating patterns of a skilled operator are programmed for raking, pushing, moving, and measuring so that they are automatically applied to the underwater rubble leveling work of the robot.