궤도-지반 상호작용 이론을 활용한 해저궤도차량의 구동성능 평가

백성하,신규범,권오순,정충기 한국지반공학회 2018 한국지반공학회논문집 Vol.34 No.2

Underwater tracked vehicle is employed to perform underwater heavy works on saturated seafloor. When an underwater tracked vehicle travels on the seafloor, shearing action and ground settlement take place on the soil-track interface, which develops the soil thrust and soil resistance, respectively, and they restrict the tractive performance of an underwater tracked vehicle. Thus, unlike the paved road, underwater tracked vehicle performance does not solely rely on its engine thrust, but also on the soil-track interaction. This paper aimed at evaluating the tractive performance of an underwater tracked vehicle with respect to ground conditions (soil type, and relative density or consistency) and vehicle conditions (weight of vehicle, and geometry of track system), based on the soil-track interaction theory. The results showed that sandy ground and silty sandy ground generally provide sufficient tractions for an underwater tracked vehicle whereas tractive performance is very much restricted on clayey ground, especially for a heavy-weighted underwater tracked vehicle. Thus, it is concluded that an underwater tracked vehicle needs additional equipment to enhance the tractive performance on the clayey ground.

An Autonomous Underwater Vehicle as an Underwater Glider and Its Depth Control

주문갑,Zhihua Qu 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.5

To provide a conventional autonomous underwater vehicle with gliding capability, we assume a moving battery and a buoyancy bag installed in a torpedo shaped autonomous underwater vehicle. We develop a mathematical model for the underwater vehicle and derive a stable gliding condition for it. Then an LQR controller is designed to control the zigzag depth of the vehicle, where the derived gliding condition is used as set-points of the control system. For control efforts in the gliding movement, the changes in the center of gravity and the net buoyancy are used, but neither thruster nor rudders are used. By using the gliding capability, the underwater vehicle can move to a farther location silently with less energy consumption and then start operating as a normal autonomous underwater vehicle. We show the feasibility of the proposed method by simulations using Matlab/Simulink.

무인 잠수정 연구 개발 동향 분석 및 발전 방안

이지은(Ji Eun Lee) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.9

무인 잠수정은 접경지역이나 적 잠수함이나 잠수정이 출몰하는 위협지역에서 감시 정찰 임무 가능한 주요 무기체계로 국내 · 외에서 활발한 연구 개발이 진행되고 있다. 무인 잠수정의 주요 활용처는 민수 분야에서는 해저 자원 탐사, 재난 예측, 해저 지형 조사 등에 활용가능하고, 국방 분야에서는 위협 지역이 등에서 적 잠수함/정 등에 대한 대잠 정찰, 기뢰 제거 등에 활용 가능하다. 본 논문에서는 무인 잠수정의 무게별, 임무별 주요 분류에 대해서 살펴보고, 무게별 주요분류 기준에 따라 휴대용급, 경량급, 중량급, 대형급 무인 잠수정의 국외 개발 동향을 조사 · 분석한다. 이를 기반으로 국내 무인 잠수정 개발 동향을 조사 · 분석하여 국외 대비 국내 현황을 살펴본다. 또한 앞서 조사 · 분석된 국내 · 외 주요 무인잠수정 개발 현황을 통하여, 본 논문에서는 미래 국내 무인 잠수정의 핵심 기술로 은밀성 강화와 통합 전장 운영이 가능한 자율제어 기술, 수중 장기 체류가 가능한 차세대 에너지원 기술, 소형화 및 경량화 기반의 정밀 센서 기술 등 미래 무인잠수정에 대한 발전 방안을 제시한다. An unmanned underwater vehicle is a major weapon system that allows surveillance and reconnaissance missions in border areas or threatening areas where enemy submarines are present. Unmanned underwater vehicles can be used to explore underwater resources, predict disasters, and survey the topography of the ocean floor in the civilian fields, while in the defense fields, it can be used for anti-submarine reconnaissance and mine countermeasures. In this paper, we first investigate the main classification of unmanned underwater vehicles, and foreign R&D trends are analyzed based on the main classification criteria by weight, such as portable, light, heavy and large-scale unmanned underwater vehicles. Then we examine the trends in the development of domestic unmanned underwater vehicles. Finally, through the analysis of both domestic and foreign unmanned underwater vehicles, we present future development trends of unmanned underwater vehicles in order to set defense goals to counter the anticipated threats and diversified potential environment.

수중 원통형 쉘 구조물의 고주파 진동 전달특성에 대한 실험적 연구

정현기(Hyun-Gi Jung),민천홍(Cheon-Hong Min),박한일(Han-Il Park) 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

Underwater vehicles such as a UUV(Unmanned Underwater Vehicle) and a ROV(Remotely Operated Vehicle) use the sonar in order to detect underwater environment or other underwater vehicles. The underwater vehicles designed recently have a high rotation and power electric propulsion system. This system can generate high frequency vibrations above 10kHz and these vibrations have bad effects on the performance of the sonar. In many previous investigations, numerical analyses for high frequency vibration problem have been used. In this study, an experimental analysis is carried out and a circular cylindrical shell is considered as a hull structure of underwater vehicle. Frequency transfer functions for the circular cylindrical shell are identified by experimental vibration analysis in the air and in fully-submerged condition. We compare frequency transfer functions in the air and water to obtain hydro-elastic effects. It is found that dynamic characteristics of the circular cylindrical shell are changed by the variation of response position.

Autonomous swimming technology for an AUV operating in the underwater jacket structure environment

이계홍,Daegil Park,Geonhui Ki 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

This paper presents the autonomous swimming technology developed for an Autonomous Underwater Vehicle (AUV) operating in the underwater jacket structure environment. To prevent the position divergence of the inertial navigation system constructed for the primary navigation solution for the vehicle, we've developed kinds of marker-recognition based underwater localization methods using both of optical and acoustic cameras. However, these two methods all require the artificial markers to be located near to the cameras mounted on the vehicle. Therefore, in the case of the vehicle far away from the structure where the markers are usually mounted on, we may need alternative position-aiding solution to guarantee the navigation accuracy. For this purpose, we develop a sonar image processing based underwater localization method using a Forward Looking Sonar (FLS) mounted in front of the vehicle. The primary purpose of this FLS is to detect the obstacles in front of the vehicle. According to the detected obstacle(s), we apply an Occupancy Grid Map (OGM) based path planning algorithm to derive an obstacle collision-free reference path. Experimental studies are carried out in the water tank and also in the Pohang Yeongilman port sea environment to demonstrate the effectiveness of the proposed autonomous swimming technology.

Autonomous swimming technology for an AUV operating in the underwater jacket structure environment

Li, Ji-Hong,Park, Daegil,Ki, Geonhui The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

This paper presents the autonomous swimming technology developed for an Autonomous Underwater Vehicle (AUV) operating in the underwater jacket structure environment. To prevent the position divergence of the inertial navigation system constructed for the primary navigation solution for the vehicle, we've developed kinds of marker-recognition based underwater localization methods using both of optical and acoustic cameras. However, these two methods all require the artificial markers to be located near to the cameras mounted on the vehicle. Therefore, in the case of the vehicle far away from the structure where the markers are usually mounted on, we may need alternative position-aiding solution to guarantee the navigation accuracy. For this purpose, we develop a sonar image processing based underwater localization method using a Forward Looking Sonar (FLS) mounted in front of the vehicle. The primary purpose of this FLS is to detect the obstacles in front of the vehicle. According to the detected obstacle(s), we apply an Occupancy Grid Map (OGM) based path planning algorithm to derive an obstacle collision-free reference path. Experimental studies are carried out in the water tank and also in the Pohang Yeongilman port sea environment to demonstrate the effectiveness of the proposed autonomous swimming technology.

Development of a Wireless Charging System based on LLC Resonant Converter for Underwater Drone

Jia-Wei Liu,Yu-Shan Cheng,Kun-Che Ho 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

Autonomous underwater vehicles (AUV), also known as underwater drones, often play the important role of assisting humans to complete the tasks of ocean exploration, monitoring, and inspection of underwater infrastructure. However, the limited power supplied by batteries has restricted the navigation tasks of underwater vehicles. The development of a wireless power transfer (WPT) system for AUVs can be regarded as an important first step to realize a fully unmanned underwater vehicle. Therefore, this paper aims to develop a wireless power transfer system suitable for underwater vehicles to solve charging issues in an underwater environment. Considering the special environment with seawater as the medium, a 200W WPT charging system is implemented based on the full-bridge LLC resonant circuit combined with the loosely coupled coil and the step-down circuit. The experimental results have validated the system is able to operate in an underwater environment with the efficiency up to 90.17% in freshwater and 87.05% in seawater.

Design of Self-Tuning Gain Depth Controller for an Autonomous Underwater Vehicle with Mass Shifter Mechanism

Mai Ba Loc,Hyeung-Sik Choi 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

This paper presents a design of self-tuning gain depth controller for the autonomous underwater vehicle KAUV-1 which has been under development at the Intelligent Robot & Automation Lab, Korea Maritime University (KIAL). The vehicle is shaped like a torpedo with light weight and small size and used for marine exploration and monitoring. The KAUV-1 has a unique ducted propeller located at aft end with yawing actuation acting as a rudder. For depth control, the KAUV-1 uses a mass shifter mechanism to change its center of gravity, consequently, can control pitch angle and depth of the vehicle. A design of classical PD depth controller for the KAUV-1 was presented and analyzed in [11]. However, it has inherent drawback of gains, that is their values are fixed. Meanwhile, in different operation modes, vehicle dynamics might have different impacts on the behavior of the vehicle, for example, ones in modes of diving and moving up as mentioned in [11]. This requires a set of flexible or self-tuning gains, i.e., their values are appropriately changed according to vehicle operating states, for a better performance. This paper presents a self-tuning gain depth controller using fuzzy logic method which based on the classical PD controller derived from [11]. Its self-tuning gains are outputs of fuzzy logic blocks. Fuzzy logic is a simple and efficient control method very suitable for this case because it could be designed based on designer’s sense and experience with flexible rules without a model. The performance of the self-tuning gain controller will be simulated by Matlab/Simulink and compared to the one of the classical PD controller.

물고기의 추진을 모방한 로봇의 개발

조강진(Kang-Jin Cho),박해원(Hae-Won Park),김석우(Seok-Woo Kim),양현석(Hyun-Suk Yang),박영필(Young-Pil Park),박노철(No-Cheol Park) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

Biological swimmers, such as fish, have several good characteristics that the man-made underwater vehicles do not have. Many scientists calculated efficiency of the fish locomotion and found that it is more efficient than conventional underwater vehicle. And fishes are usually more maneuverable than the conventional underwater vehicles. Some fishes can make a whole turning with the diameter of one body length. Predatory fishes accelerate at 12Gs from stationary state. On the other hand, man-made underwater vehicles suffer from serious lag times in transient response, and their turning radius is larger than that of fishes. Recent underwater vehicle has problems of short battery life due to low efficiency, poor maneuvering ability, and restricted payloads due to large battery size. Therefore we developed a robot that mimics fish locomotion so that we could expect characteristics of fish locomotion from underwater vehicle.

Influence of a simulated deep sea condition on the cathodic protection and electric field of an underwater vehicle

Kim, Y.-S.,Lee, S.K.,Chung, H.-J.,Kim, J.-G. Elsevier 2018 Ocean engineering Vol.148 No.-

<P><B>Abstract</B></P> <P>To investigate the effect of the deep sea condition on the corrosion behavior, cathodic protection and electric field of underwater vehicles, potentiodynamic polarization tests were carried out under a simulated deep sea condition. A 3-D boundary element method (BEM) was used for an underwater vehicle with and without sacrificial anode cathodic protection (SACP). The simulated deep sea condition influenced the cathodic polarization curves due to the difference between the cathodic reactions. Under the deep sea condition, the cathodic protection potential criterion was more easily satisfied as the protection current density of SACP was decreased. The electric field underneath the underwater vehicle showed that the deep sea condition decreased the electric field due to the lower current density and the shape of the electric field distribution changed from one dipole to two dipoles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cathodic protection and electric field of an underwater vehicle in simulated deep sea condition were investigated. </LI> <LI> Boundary element method was used for the sacrificial anode cathodic protection of an underwater vehicle. </LI> <LI> Simulated deep sea condition influences the cathodic polarization curves due to the difference of the cathodic reaction. </LI> <LI> The electric field below the underwater vehicle shows that the deep sea condition decreased the electric field. </LI> </UL> </P>