해양 글라이더에 관하여: 한국 근해에서의 적용 가능성

박종진 한국해양과학기술원 2013 Ocean and Polar Research Vol.35 No.2

The underwater glider is an autonomous vehicle that can glide through the ocean interior by using a pair of wings attached to its body and can move up and down through the water column by changing its buoyancy. As of now, there are three widely-used gliders, namely, the Spray that was codeveloped by Scripps Oceanographic Institution and Woods Hole Oceanographic Institution, the Slocum produced by the Webb Research Cooperation, and the Seaglider that was produced by the University of Washington. In this paper, I will introduce these three gliders and discuss the principles and procedures related to glider operation as well as the application and extendability of modern physical and biogeochemical sensors to gliders. My experiences in developing a glider for measuring ocean turbulence and testing it 7 times during 12 days are shared in this paper. On the basis of my experiences and knowledge, different kinds of aspects that should be considered for successful glider operation are discussed. In addition, a suggestion is made as to what would be the ideal way to operate underwater gliders in the East/ Japan Sea. At the end, the current status of active glider operation teams is presented and the efforts to proceed toward future gliders are briefly introduced.

Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

Sun, Chunya,Song, Baowei,Wang, Peng The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.6

Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as long-range, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

Dynamics Modeling and Behavior Analysis of Underwater Glider System

Nam, Keon-Seok,Kim, Donghee,Choi, Hyeung-Sik,Lee, Shin-je,Kim, Joon-Young Korean Society of Ocean Engineers 2017 Journal of advanced research in ocean engineering Vol.3 No.1

Generally, underwater gliders do not have separate propellers for their forward movement. They derive a propulsive force due to the difference between their buoyancy and gravity. The attitude of an underwater glider is controlled by changing the relative position of the buoyancy center and mass center. In this study, we derived nonlinear 6-DOF dynamic and mathematical models for the motion controller and buoyancy controller. Using these equations, we performed dynamic underwater glider simulations and verified the suitability of the design and dynamic performance of the proposed underwater glider.

이동질량장치와 부력엔진을 포함한 무인 수중글라이더의 동역학 모델링 및 운동성능 해석

김동희(Donghee Kim),이상섭(Sang Seob Lee),최형식(Hyeung Sik Choi),김준영(Joon Young Kim),이신제(Shinje Lee),이용국(Yong Kuk Lee) 한국해양공학회 2014 韓國海洋工學會誌 Vol.28 No.5

Underwater gliders do not have any external propulsion systems that can generate and control their motion. Generally, underwater gliders would obtain a propulsive force through the lift force generated on the body by a fluid. Underwater gliders should be equipped with mechanisms that can induce heave and pitch motions. In this study, an inner movable and rotatable mass mechanism was proposed to generate the pitch and roll motions of an underwater glider. In addition, a buoyancy control unit was presented to adjust the displacement of the underwater glider. The buoyancy control unit could generate the heave motion of the underwater glider. In order to analyze the underwater dynamic behavior of this system, nonlinear 6-DOF dynamic equations that included mathematical models of the inner movable mass and buoyancy control unit were derived. Only kinematic characteristics such as the location of the inner movable mass and the piston position of the buoyancy control unit were considered because the velocities of these systems are very slow. The effectiveness of the proposed dynamic modeling was verified through sawtooth and spiraling motion simulations.

수중글라이더를 활용한 동해 아중규모 중층성 소용돌이 발견

박종진,PARK, JONGJIN 한국해양학회 2019 바다 Vol.24 No.2

2017년 8월 7일부터 25일까지 수중글라이더를 활용하여 $37.9^{\circ}N$ 위도 라인를 따라 동경 $129.0^{\circ}E{\sim}131.3^{\circ}E$ 사이를 왕복하는 단면 관측을 수행하였다. 해당 경로는 국립수산과학원 정기선박 관측라인 중 106 라인을 따른 것으로 이 경로를 따라 약 18일간 운용하였으며 위치 유지 모드로 동작했던 시간을 제외하고 총 440 km를 비행하였고, 그동안 고해상도 수온 및 염분의 공간 단면을 관측하였다. 본 관측 해역은 약 0.8 m/s의 강한 유속을 갖는 동한난류가 북상하고 있는 상황이었음에도 불구하고, 해당 수중글라이더는 지정된 경로에서부터 RMS 거리 400 m 이내를 벗어나지 않고 정확하게 106 라인을 따라 비행하였다. 본 관측에서 얻어진 고해상도 물성 단면 구조를 국립수산과학원 정선 관측 자료와 비교함으로써 해양환경에 지대한 영향을 끼치는 전선역이나 소용돌이와 같은 현상을 관측하기 위해서 고해상도 관측이 얼마나 중요한지 확인할 수 있었다. 이러한 수중글라이더 관측을 통해 이제까지 발견하지 못했던 새로운 소용돌이를 발견할 수 있었다. 이 소용돌이는 수평폭이 10~13 km, 수직폭은 200 m 가량되는 렌즈 형태를 가지고 있으며 시계방향으로 회전하는 아중규모 중층성 소용돌이(submesoscale intrathermocline eddy)다. 수온약층 내 혹은 직하부에 존재하면서 아중규모의 렌즈형태의 구조를 갖는 이러한 중층성 소용돌이는 동해에서 처음 발견되었기 때문에 Korea intrathermocline eddy(Keddy)로 명명하였다. 이 Keddy는 다음과 같은 전형적인 중층성 소용돌이(intrathermocline eddy)의 특징을 가지고 있다. Keddy는 수온약층 하부인 수심 약 170 m, 즉 중층에서 유속최대값을 갖는 특징이 있고, 따라서 해표면에는 해당 지오포텐셜 구조가 드러나지 않는 2차 순압성 구조를 가지고 있다. 또한 중앙부의 성층화가 주변보다 약하고, 수평크기가 1차 순압성 로스비 변형반경과 유사하며, 로스비 수가 0.7로 1에 근접한다. Zonal hydrographic section measurements at $39.7^{\circ}N$ were conducted between $129.0^{\circ}E$ and $131.3^{\circ}E$ from August 7 to 25 in 2017 using an underwater glider. The glider traveled about 440 km for about 18 days along the 106 line of the regular shipboard measurements in the National Institute of Fishery Science (NIFS) and obtained twice a hydrographic section with high horizontal resolution. Even under the strong East Korea Warm Current with maximum speed of 0.8 m/s across the section, the glider successfully maintained the designated path within an RMS distance of 400 m. By comparing with the NIFS shipboard hydrographic section, it is confirmed that high spatial resolution measurements obtained from a glider were necessary to properly observe front and eddy variability in the East Sea where a typical spatial scale is smaller than the open oceans. From the glider section measurements, a new lens-shaped eddy was found in the thermocline. The lens-shaped anticyclonic eddy had 10~13 km in horizonal width and about 200 m in height like a typical submesoscale eddy resided within the thermocline, which was firstly named as Korea intrathermocline eddy (Keddy). The Keddy has the distinguishing characteristics of a typical intrathermocline eddy, such as a central core with anomalously weak stratification, a convex shaped lens bounded by the stratification anomaly, an interior maximum of velocity at 170 m, no surface appearance of the geopotential field, a small or comparable horizontal width relative to the first baroclinic Rossby radius of deformation, and the Rossby nubmer of 0.7.

Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

Chunya Sun,Baowei Song,Peng Wang 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.6

Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as longrange, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

A controller comprising tail wing control of a hybrid autonomous underwater vehicle for use as an underwater glider

Joo, Moon G. The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

A controller for an underwater glider is presented. Considered underwater glider is a torpedo-shaped autonomous underwater vehicle installing adjustable buoyancy bag and movable battery in it. The controller is composed of an LQR controller to maintain zigzag vertical movement for gliding and two PD controllers to control elevator/rudder angles. The LQR controller controls the pumping speed into the buoyancy bag and the moving speed to locate the battery. One of the PD controller controls the elevator angle to assist the LQR controller, and the other controls the rudder angle to adjust the direction of the underwater glider. A reduced order Luenberger observer is adopted to estimates the center of gravity of the glider and the buoyancy mass that are essential but cannot be measured. Mathematical simulation using Matlab proved the validity of the proposed controller to obtain better performance than conventional LQR only controller under the influence of sea current.

A controller comprising tail wing control of a hybrid autonomous underwater vehicle for use as an underwater glider

Moon G. Joo 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

A controller for an underwater glider is presented. Considered underwater glider is a torpedo-shaped autonomous underwater vehicle installing adjustable buoyancy bag and movable battery in it. The controller is composed of an LQR controller to maintain zigzag vertical movement for gliding and two PD controllers to control elevator/rudder angles. The LQR controller controls the pumping speed into the buoyancy bag and the moving speed to locate the battery. One of the PD controller controls the elevator angle to assist the LQR controller, and the other controls the rudder angle to adjust the direction of the underwater glider. A reduced order Luenberger observer is adopted to estimates the center of gravity of the glider and the buoyancy mass that are essential but cannot be measured. Mathematical simulation using Matlab proved the validity of the proposed controller to obtain better performance than conventional LQR only controller under the influence of sea current.

리야푸노프 직접법에 의한 수중 글라이더의 깊이 제어

주문갑,Joo, Moon Gab 대한임베디드공학회 2017 대한임베디드공학회논문지 Vol.12 No.2

To control the depth of an underwater glider, a control method by using Lyapunov's direct method is proposed. The underwater glider has a torpedo-shape hull, a movable mass in the hull, and an inflatable buoyancy bag in the hull, but doesn't have large wings that increase the lift force for the conventional underwater glider. The control laws to adjust the position of the movable mass and the mass of the inflatable buoyancy bag are derived. For a selected speed and an angle of attack, we simulated the operation of the underwater glider using Matlab/Simulink. The efficiency of the proposed controller is shown in the fact that the control effort is active during only a short period of time when the zigzag trajectory is changed from downward to upward or vice versa.

Ray형 수중글라이더 소형 축소모델 개발 및 성능시험

최형식 ( Hyeung-sik Choi ),이성욱 ( Sung-wook Lee ),강현석 ( Hyeon-seok Kang ),( Nguyen Ngoc Duc ),김서강 ( Seo-kang Kim ),정성훈 ( Seong-hoon Jeong ),( Peter C. Chu ),김준영 ( Joon-young Kim ) 한국항행학회 2017 韓國航行學會論文誌 Vol.21 No.6

수중글라이더(UG; underwater glider)는 지속적인 해양관측·탐사를 목적으로 개발된 장기운용 가능한 수중로봇이다. 원통형의 일반적인 수중글라이더는 단일 부력엔진과 자세제어기를 통해 추진하기 때문에, 운동조종성능 측면에서 효율적이지 못하다. 본 논문에서는 기존 원통형 수중글라이더의 부력제어 및 운동제어성능을 개선하기 위해 이중부력엔진을 탑재한 가오리 형태의 수중글라이더를 소개한다. CFD(computational fluid dynamics) 해석을 수행하여 설계된 형상의 글라이드 운동에 대한 유체저항성능을 해석한다. 산출한 유체력 계수를 바탕으로 운동 시뮬레이션을 수행하여 운동성능을 비교·분석한다. 가오리 형태의 수중글라이더 소형 축소모델을 제작하고, 제어시스템을 구성하여 기초 성능시험을 수행한다. Underwater glider is the long-term operating underwater robot that was developed with a purpose of continuous oceanographic observations and explorations. Torpedo-type underwater glider is not efficient from an aspect of maneuverability, because it uses a single buoyancy engine and motion controller for obtaining propulsive forces and moments. This paper introduces a ray-type underwater glider(RUG) with dual buoyancy engine, which improves the control performance of buoyancy and motion compared with torpedo-type underwater glider. Carrying out Computational Fluid Dynamics (CFD) analysis as static pitch drift test, the performance of fluid resistance for gliding motion was identified. Based on the calculated hydrodynamic coefficients, the dynamic simulation compared and analyzed the motion performance of torpedo-type and ray-type while controlling same volume of buoyancy engine. Small-sized model of RUG was developed to perform fundamental performance tests.