• 한국해양공학회지
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• 제22권4호
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• pp.97-105
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• 2008

This paper represents the experimental identification of a finite-dimensional dynamical plant model for the HEMIRE Remotely Operated Vehicle. The experiments were conducted during sea trials in the East Sea in October 2006 and peer testing by the South Sea Research Institute in January 2007. A least-squares method was employed to identify decoupled single degree-of-freedom plant dynamical models for the X, Y, Z and heading degree-of-freedom from experimental data. The performance of the identified plant dynamical model was evaluated by directly comparing simulations of the identified plant model to the experimentally observed motion data from the actual vehicle.

• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.797-804
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• 2013

In this paper, a study of a new hovering six dof underwater robot with redundant horizontal thrusters, titled HAUV (hovering AUV), is presented. The results of study on the structure design, deployment of thrusters, and development of the developed control system of the AUV was presented. For the HAUV structure, a structure design and an analysis of the thrusting system was performed. For navigation, a sensor fusion board which can proceed various sensor signals to identify correct positions and speeds was developed and a total control system including EKF (Extended Kalman Filter) was designed. Rolling, pitching and depth control tests of the HAUV have been performed, and relatively small angle error and depth tracking error results were shown.

• Journal of Advanced Marine Engineering and Technology
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• 제36권4호
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• pp.451-458
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• 2012

수중의 작업 목적에 따라 ROV와 AUV의 두 가지 용도로 사용할 수 있는 새로운 구조의 변신 6자유도 수중로봇의 설계연구를 하였다. CROV의 ROV모드와 AUV모드에 대한 각각의 구조 설계연구를 수행하였으며 각각의 모드에 대한 제어시스템을 설계하고 AUV의 경우에는 추력에 따른 항해속도에 대한 해석을 수행하였다. ROV나 AUV의 정확한 위치 및 속도를 추정할 수 있도록 다양한 센서신호를 퓨전하여 처리하는 센서퓨전보드를 제작하고 확장 칼만필터를 포함하는 전체 제어시스템을 설계하고 제작하였다.

• 한국기계가공학회지
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• 제19권4호
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• pp.85-92
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• 2020

Applications for the unmanned aerial vehicle (UAV) have expanded enormously in recent years. Of all its various technologies, the UAV's ability to take off and land in a moving environment is particularly required for military or oceanic usage. In this study, we develop a novel leveling platform that allows the UAV to stably take off and land even on uneven terrains or in moving environments. The leveling platform is composed of an upper pad and a lower mobile base. The upper pad, from which the UAV can take off or land, is designed in the form of a 2 degrees of freedom (DOF) gimbal mechanism that generates the leveling function. The lower mobile base has a four-wheel drive structure that can be operated remotely. We evaluate the developed leveling platform by performing extensive experiments on both the horizontal terrain and the 5-degree ramped terrain, and confirm that the leveling platform successfully maintains the horizontal pose on both terrains. This allows the UAV to stably take off and land in moving environments.

• 대한조선학회논문집
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• 제51권2호
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• pp.148-153
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• 2014

Submerged bodies such as autonomous underwater vehicles (AUV) or remotely operated vehicles (ROV) are widely used in various fields of exploring underseas. Those bodies keep ballasting and deballasting for stable navigation and operation. Identifying the internal volumetric spaces of the bodies is a primary step for such an operation. Unfortunately, most CAD models given to the engineer do not properly represent the compartments since each face of a compartment exists as an independent entity rather than as a face that belongs to the compartment. In this paper, an algorithm that automatically identify the faces as a group that forms a closed volumetric space, i.e., a compartment is presented. A submerged body is sliced into a number of cross sections. Each sliced section is analyzed to yield closed loops that are sections of the compartment. Then, the associated closed loops are gathered along the longitudinal direction to form a compartment. The algorithm presented is shown to provide a practical and reasonable solution that can readily be used in various applications.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권2호
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• pp.313-323
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• 2013

Offshore floating structures have so-called moonpool in the centre area for the purpose of drilling, installation of subsea structures, recovery of Remotely-Operated Vehicle (ROV) and divers. However, this vertical opening has an effect on the operating performance of floating offshore structure in the vicinity of moonpool resonance frequency; piston mode and sloshing mode. Experimental study based on model test was carried out. Moonpool resonance of floating offshore structure on fixed condition and motion free condition were investigated. And, the effect of cofferdam which is representative inner structure inside moonpool was examined. Model test results showed that Molin's theoretical formula can predict moonpool resonance on fixed condition quite accurately. However, motion free condition has higher resonance frequency when it is compared with that of motion fixed. The installation of cofferdam moves resonance frequency to higher region and also generates secondary resonance at lower frequency. Furthermore, it was found that cofferdam was the cause of generating waves in the longitudinal direction when the vessel was in beam sea.

• 산업기술연구
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• 제25권A호
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• pp.81-86
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• 2005

A vibration monitoring system for a small class of wind turbine (W/T) is established and operated. The monitoring system consists of monolithic integrated chip accelerometer for vibration monitoring, anemometers for wind data acquisition and auxiliary sensors for atmospheric data. Using the monitoring system, vibration response of a 6kW W/T generator is investigated. Acceleration data of the W/T tower under various operation condition is acquired in real time using LabVIEW and is remotely transferred from the test site to the laboratory in school by internet. Vibration state of the tower structure is diagnosed within the operating speed range. Resonance frequency range of the test model is investigated with the wind speed data of the test site.

• 한국해양공학회지
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• 제25권5호
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• pp.58-63
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• 2011

Underwater vehicles such as UUVs (Unmanned Underwater Vehicles) and ROVs (Remotely Operated Vehicles) use sonar to detect their underwater environment or other underwater vehicles. The underwater vehicles designed recently have an electrical power system with high rotational speed. This system can generate high frequency vibrations above 10 kHz, and these vibrations can cause bad (negative) effects on the performance of the sonar. In many previous investigations, numerical analyses have been used for high frequency vibration problems. In this study, an experimental analysis was carried out, and a circular cylindrical shell was considered as the hull structure of an underwater vehicle. Frequency transfer functions for the circular cylindrical shell were identified using an experimental vibration analysis in the air and in a fully-submerged condition. We compare the frequency transfer functions in the air and water to obtain hydro-elastic effects. It is found that the dynamic characteristics of the circular cylindrical shell are changed by varying the response position.

• 대한조선학회논문집
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• 제45권6호
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• pp.579-589
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• 2008

In the past few years, there are many studies and researches of the underwater vehicles which are carried out its mission using sonar sensors. MSCL(Marine System Control Lab.) at Inha University developed test-bed small ROV, ISRO. ISRO is an open-frame type and has 4 thrusters. ISRO can control 4 motions i.e surge, sway, yaw and heave with sonar sensors. ISRO is developed for inspection of ship hull, marine structure, plant of lake or river and so on. When ROV ISRO inspects something, it is necessary to control the position of ROV ISRO's for the movement and anti-collision with structures in the underwater. In this paper, we deal with the development of a small ROV and verification of the position control system via simulation and experiment using sonar sensors.

• 한국컴퓨터정보학회논문지
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• 제22권6호
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• pp.123-129
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• 2017

In this paper, we proposed a smart multiple-tap system which a remote user with smartphone can control multiple-taps in order to reduce standby-power consumption more conveniently when plugged-in electric appliances are turned-off. Recently, several researches of smart multiple-tap using IoT technology has reported. However, in these researches, an additional device like as a server computer is necessary, or multiple-taps could be only remotely controlled by smartphone and not directly controlled by on/off switch. The proposed smart multiple-tap system does not need any additional device only if it has a WiFi router, and it can be used for user as well as remote control using smartphone application and physically direct control using contact switches like existing multiple-taps. Our approach is to develop a smart multiple-tap device capable of WiFi communication can each serve as a server or a client, and can be operated by the hybrid switch combining the on/off contact switch and the relay switch. We implemented the prototype of the proposed system composed of the smart multiple-tap device and the smartphone application, and the test of the prototype validates the proposed system.