• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.199-203
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• 2017

In this paper, we developed an underwater localization system for underwater robot docking using the electromagnetic wave attenuation model. Electromagnetic waves are generally known to be impossible to use in water environment. However, according to the conclusions of the previous studies on the attenuation characteristics in underwater, the attenuation pattern is uniform and its model was accurately proposed and verified in 3-dimensional space via the omnidirectional antenna. In this paper, a docking structure and localization sensor system are developed for a widely used cone type docking mechanism. First, we fabricated electromagnetic wave range sensor transmit modules. And a mobile sensor node is equipped with unmanned underwater vehicle(UUV)s. The mobile node senses the four different signal strength (RSS: Received Signal Strength) from fixed nodes, and the obtained RSS data are transformed to each distance information using the 3-Dimensional EM wave attenuation model. Then, the relative localization between the docking area and underwater robot can be achieved according to optimization algorithm. Finally, experimental results show the feasibility of the proposed localization system for the docking induction by comparing the errors in the actual position of the mobile node and the theoretical position through the model.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.170-178
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• 2017

This paper proposes an improved path-planning technique based on the $A^*$ algorithm. The conventional $A^*$ algorithm only considers the optimality of the planned path and sometimes produces a path that an unmanned underwater vehicle (UUV) cannot navigate due to its dynamic constraint such as the limit of the radius of gyration. It is because that the previous method evaluate the moving cost based on the straight distance between nodes. We enhance the conventional method by evaluating the moving cost on the basis of the practically navigable trajectory, which is generated by the waypoint-tracking control of the UUV dynamics. The simulation examples indeed show the effectiveness of the proposed technique.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.781-787
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• 2011

Mine countermeasure missions(MCMs) may induce the loss of human and ship because of the covert of mine. In recent years, unmanned underwater vehicles(UUVs) have emerged as viable technical solution for conductimg underwater search, surveillance, and clearance operations in support of mine countermeasure missions because of her autonomy and long time endurance capability. This paper introduces a technical approach to mine countermeasure mission effectiveness analysis and presents some simulation-based analysis results for engineering of the UUV system definition which could be support analysis of alternatives for system definition and design.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.410-416
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• 2012

In recent years, unmanned underwater vehicles(UUVs) have emerged as viable technical solution for conducting underwater search, surveillance, and clearance operations in support of mine countermeasure missions(MCMs) because of her autonomy and long time endurance capability. It is necessary for UUV for MCM system design to define system specification from various configuration alternatives. This paper introduces a simulation model for mine countermeasure mission effectiveness analysis and presents some simulation results under various tide conditions for validation of the proposed simulation model.

• Journal of KIISE:Software and Applications
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• v.34 no.3
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• pp.235-245
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• 2007

UUV(Unmanned Underwater Vehicle) should possess an intelligent control software performing intellectual faculties such as cognition, decision and action which are parts of domain expert's ability, because unmanned underwater robot navigates in the hazardous environment where human being can not access directly. In this paper, we suggest a RVC intelligent system architecture which is generally available for unmanned vehicle and develope an autonomous navigation system for UUV, which consists of collision avoidance system, path planning system, and collision-risk computation system. We present an obstacle avoidance algorithm using fuzzy relational products for the collision avoidance system, which guarantees the safety and optimality in view of traversing path. Also, we present a new path-planning algorithm using poly-line for the path planning system. In order to verify the performance of suggested autonomous navigation system, we develop a simulation system, which consists of environment manager, object, and 3-D viewer.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.151-151
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• 2023

An accurate prediction of the hydrodynamic maneuvering darivatives is essential to desing a robust control system of a UUV(unmanned underwater vehicle). Typically, these derivatives were estimated by either the towing tank experiment or semi-empirical methods. With the enhancement of high performance computing capacity, a numerical analysis using computational fluid dynamics has reach the level of experiment. Therefore, the aims of the present research are to numerically develop a computational model for the vertical planar motion mechanism of a UUV and to estimate the hydrodynamics loads in 6-DOF. The target structure of the present study was manta type UUV (12meter length). The numerical model was developed in 1/ 6 model scale. Numerical results were compared with the results of the towing tank experiment for validation. In the present study, a commercial RANS-based viscous solver STARCCM+ (ver 17.06) was used.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.562-569
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• 2016

This paper proposes a navigation system with a robust localization method for an underwater unmanned vehicle. For robust localization with IMU (Inertial Measurement Unit), a DVL (Doppler Velocity Log), and depth sensors, the EKF (Extended Kalman Filter) has been utilized to fuse multiple nonlinear data. Note that the GPS (Global Positioning System), which can obtain the absolute coordinates of the vehicle, cannot be used in the water. Additionally, the DVL has been used for measuring the relative velocity of the underwater vehicle. The DVL sensor measures the velocity of an object by using Doppler effects, which cause sound frequency changes from the relative velocity between a sound source and an observer. When the vehicle is moving, the motion trajectory to a target position can be recorded by the sensors attached to the vehicle. The performance of the proposed navigation system has been verified through real experiments in which an underwater unmanned vehicle reached a target position by using an IMU as a primary sensor and a DVL as the secondary sensor.

• The Journal of the Acoustical Society of Korea
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• v.27 no.6
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• pp.279-285
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• 2008

This study includes the efficiency assessment of a multiple access protocol for UUV (Underwater unmanned vehicle) control. Most of UUVs are controled by wire now; however, wireless control is demanded because of the demerit of the wire control that limits the place and activity. This study simulates efficiency of a standardization multiple access protocol (Pure ALOHA, Slotted ALOHA, Nonpersistent CSMA, Slotted Nonpersistent ISMA) formed for the purpose of performing wireless communication controlled by the ship or communication buoy at the sea surface and by the under water communication node at the bottom in order to efficiently control the UUV's. Results show that no significant changes occur related to changing type of the mother ship and the communication node; In addition, the Non-persistent CSMA and the Slotted Non-persistent ISMA show relatively high efficiency for underwater acoustic communication.

• The Magazine of the IEIE
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• v.38 no.7
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• pp.20-29
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• 2011

무인잠수정(Unmanned Underwater Vehicle, UUV)은 하드웨어 구성과 관련하여 ROV (Remotely Operated Vehicle), SAUV (Semi-Autonomous Underwater Vehicle), AUV (Autonomous Underwater Vehicle) 등으로 구분할 수 있으며, 그 중에서 자율무인잠수정(AUV)은 주어진 임무의 난이도, 작업 환경의 정보, 그리고 운용자의 간섭 정도에 따라 다양한 수준으로 자율 정도를 분류한다. 무인잠수정은 미국을 중심으로 1952년부터 개발되기 시작하였으며 최초는 전적으로 운용자에 의해서 직접 운용되는 ROV가 주를 이루었다. 자율무인잠수정은 1980년대부터 다양한 수중관련 기술 및 컴퓨터 발전과, 민군의 사용분야가 증가되면서 급속한 발전을 이루어 왔으며 이에 따라 AUV 자율수준 정의와 기술개발도 급속한 진전이 이루어져 왔다. 본 기고에서는 무인잠수정의 개발현황, 자율개념 및 자율수준(Autonomy Levels for Underwater Vehicle, ALFUV)의 정의, 자율을 정립함에 필요한 방법 또는 기술 등을 알아보고 마지막으로 자율 알고리즘으로 개발된 구조의 표준화를 중심으로 현황을 파악하였으며 또한 미래의 자율수준 개발 동향을 살펴보았다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.172-177
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• 2004

This paper presents the results of the structural analysis and optimal design of frames of the UUV(Unmanned Underwater vehicle) to be operated at 6000m depth in the ocean. The structure of the UUV system can be classified into two structure, Launcher ana ROV. Frame of the launcher will be made by Galvanized Steel which has high strength and corrosion-resistant but this material has high specific gravity for tile object to be weight in the water Similarly, ROV will be made by AI6061-T6, and frame of the ROV will be fix many instruments and syntactic buoyancy materials. Before fabrication of tile frame, we performed sensitivity analysis - change in weight due to $\pm1\%$ change in design variables, for easy choice by change of dimension of the frame.