• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.33-40
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• 2014

Due to its unmanned feature and some of being matured underwater technologies, UUV(Unmanned Undersea Vehicle) is increasingly considered as a utility player in today's battle-field. The operational benefit of submarine-based UUV operation could be enormous yet the integration challenges are significant, particularly for most of small conventionally-powered submarines. In this paper, we consider UUV operational methodology via the conventional submarine's torpedo tube. Two previous attempts having been done to retrieve the UUV through torpedo tube are reviewed, and their pros and cons are also analyzed. Then, an alternative option is proposed for UUV operation via torpedo tube. In addition, some of practical challenges are also discussed in the paper.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.454-461
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• 2019

In autonomous interventions using an underwater vehicle with a manipulator, grasping based on target detection and recognition is one of the core technologies. To complete an autonomous grasping task, the vehicle body approaches the target closely and then holds it through operating the end-effector of the manipulator, while the vehicle maintains its position and attitude without unstable motion. For vehicle motion control, it is very important to identify the hydrodynamic parameters of the underwater vehicle, including the propulsion force. This study examined the propulsion characteristics of the autonomous intervention ROV developed by KRISO, because there is a difference between the real exerted force and the expected force. First, the mapping between the input signal and thrusting force for each underwater thruster was obtained through a water tank experiment. Next, the real propulsion forces and moments of the ROV exerted by thrusting forces were directly measured using an F/T (force/torque) sensor attached to the ROV. Finally, the differences between the measured and expected values were confirmed.

• Journal of Ocean Engineering and Technology
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• v.32 no.4
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• pp.287-295
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• 2018

This paper presents the results of an exploration of the ferromanganese crusts of Western Pacific Seamount registered by the Korean government. This area has been surveyed with a deep-sea camera and crust samples have been acquired by deep-sea dredging since 2013. On October 18-19, 2017, a united research team from KIOST and KRISO explored two blocks, OSM11 and OSM07, on the seamount using Hemire ROV. A precise survey was conducted on the ferromanganese crusts and sediments covering the slope/top of OSM11 and the middle flat area of OSM07. Rock samples were collected with precise positioning, and HD videos were recorded for 7 hours. This paper discusses the technical issues of this exploration in terms of (1) how to deal with an emergency situation during an electric power blackout, (2) the improvement of the thruster power by adding cooling plugs to the housings of the thruster amplifiers, (3) the relative motion of the depressor by changing the fixing method of the cable terminator, which affects the service life of the cable, (4) a sampling technique for the steep slope of the seamount, (5) integrated navigation under a USBL blackout, and (6) a 3-dimensional image mosaic for visualizing the distribution state of the crusts.

• Journal of Ocean Engineering and Technology
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• v.31 no.1
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• pp.69-79
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• 2017

This paper presents the operations of a multi-beam echo sounder (MBES) installed on the deep-sea remotely operated vehicle (ROV) Hemire. Hemire explored hydrothermal vents in the Forecast volcano located near the Mariana Trench in March of in 2006. During these explorations, we acquired profiling points on the routes of the vehicle using the MBES. Information on the position, depth, and attitude of the ROV are essential to obtain higher accuracy for the profiling quality. However, the MBES installed on Hemire does not have its own position and depth sensors. Although it has attitude sensors for roll, pitch, and heading, the specifications of these sensors were not clear. Therefore, we had to merge the high-performance sensor data for the motion and position obtained from Hemire into the profiling data of the MBES. Then, we could properly convert the profiling points with respect to the Earth-fixed coordinates. This paper describes the integration of the MBES with Hemire, as well as the coordinate conversion between them. Bathymetric maps near the summit of the Forecast volcano were successfully collected through these processes. A comparison between the bathymetric maps from the MBES and those from the Onnuri Research Vessel, the mother ship of the ROV Hemire for these explorations, is also presented.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.289-299
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• 2019

Various sizes of ROVs are being utilized in offshore industrial, scientific, and military applications all around the world. Because of innovative developments in science and technology, image acquisition devices such as sonar devices and cameras have been reduced in size and their performance has been improved. Thus, we can expect better accuracy and higher resolution even in the case of exploration using a small ROV. The purpose of this paper is to prepare a standard procedure for the identification of unidentified hazardous materials found during the National Oceanographic Survey. In this paper, we propose an IDEF (Integrated DEFinition) method modeling technique to identify unidentified targets using a small ROV. In accordance with the proposed procedure, an ROV survey was carried out on target No.16 with a four-ton-class fishing boat as a support vessel on September 18th of 2018 in the sea near Daebu Island. Unidentified targets, which were not known by the multi-beam data obtained from the ship, could be identified as concrete pipes by analyzing the HD camera and high-resolution sonar images acquired by the ROV. The whole proposed procedure could be verified, and the survey with the small ROV required about 10 days to identify the target in one place.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.161-167
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• 2019

In this paper, the performance verification of an around-view sonar and an excavation depth measuring sonar applicable to track-based ROVs (Remotely Operated underwater Vehicles) for heavy duty work is studied. For the performance verification, an experiment is carried out in a water tank and at sea by attaching the around-view sonar and the excavation depth measuring sonar for a heavy work ROV. In the case of the around-view sonar, image sonars are mounted on ROV in four directions (front, back, left and right) and in the case of the excavation depth measuring sonar, the same kind of MBES (Multi Beam Echo Sounder) is mounted on the front of the ROV. The result of an operation test of the ROV equipped with these sonars shows that the sonar systems are rarely affected by high turbidity due to sedimentation during the operation. In the case of the around-view sonar, it is possible to see rock formation, gravel and sandbank 30 m ahead of the ROV. It is confirmed that the excavation depth can be measured after the ROV has performed the excavation. This experiment demonstrates that the ROV can improve the efficiency of the work by utilizing the around-view sonar and the excavation depth measuring sonar.