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TECHNICAL ASSESSMENT OF
TWO UNMANNED VEHICLES FOR

UNDERSEA RESEARCH

Two new Japanese developments in undersea technology were evaluated

during sea trials: a semi-autonomous vehicle and a new, low-light-level
camera for a remotely operated vehicle. The semi-autonomous vehicle, or
UROV (Untethered Remotely Operated Vehicle), was attached to the surface

with a 1-mm fiber optic link. The low-light-level camera, named HARP
(High-Gain Avalanche Rushing Amorphous Photoconductor), was deployed
on a 3,000-meter ROV and is a next generation for underwater camera low-

light capability. Both systems tested well and are assessed below.

by A.N. Kalvaitis and Gregory Stone

INTRODUCTION

Program in Natural Resources (UJNR). undersea vehicles (AUVs), as well as

Mr. Greg Stone, a guest researcher at bottom observatories. Proof-of-concept sea trials of two JAMSTEC, is on exchange from the These capabilities enable scientists different undersea vehicles, developed National Oceanic and Atmospheric

National Oceanic and Atmospheric to collect data, make observations, for undersea research, were observed Administration's (NOAA) National collect samples, and conduct experion 6-7 November 1991. These evalua- Undersea Research Program (NURP). ments not possible within the limitations were conducted on the UROV- The other author, Mr. A. Kalvaitis, is a tions of traditional laboratory and ship500, a battery powered remotely oper- senior engineer at NOAA-NURP in based research. Most of the research ated vehicle (ROV), and the DOLPHIN Silver Spring, Maryland. Cruise partic- supported worldwide has been con3K ROV, using an ultra-sensitive under- ipants included several engineers, among ducted from manned submersibles to water color video camera. These tests them Dr. Matsuo Hattori of JAMSTEC, depths of 6,000 meters, although there were conducted in the western part of and researchers from other Japanese has been a trend toward the utilization Sagami Bay near Hatsushima Island agencies and companies.

of unmanned vehicles such as ROVs off Atami, Japan, using the RN KAIYO

and AUVs (Ref 1 and 2). and RN NATSUSHIMA as surface BACKGROUND support vessels. The Japan Marine

UROV-500 DESCRIPTION Science and Technology Center The purpose of observing these tests AND ASSESSMENT (JAMSTEC), the primary institution was to technically assess the capability in Japan dedicated to ocean research, of these vehicles to satisfactorily con- The UROV-500 is basically a tetherwas responsible for carrying out these duct undersea research. NURP directs

duct undersea research. NURP directs less, battery powered ROV that uses investigations.

a program that is the United States an expendable fiber optic link to trans

civilian focus for meeting the undersea mit video and other data from depths PARTICIPANTS

research requirements of government, to 500 meters. These tests were con

academia, and industrial communities. ducted on 6 November, near Hatsushima The authors were invited by In-situ facilities available to this pro- Island in western Sagami Bay off the JAMSTEC to witness these sea trials gram include manned submersibles,

gram include manned submersibles, JAMSTEC support ship R/V KAIYO. under the auspices of the Panel on research habitats, and unmanned sys- More detailed information on the Diving Physiology and Technology of tems such as ROVs and autonomous KAIYO, a semisubmersible twin-hull the United States-Japan Cooperative

ship, 61.5 meters long, that allows for

450 kg

stable at sea operations, can be found control signals. System components winds were 14 m/s (28 knots) and in Reference 3.

include a control van, A-frame launcher, whitecaps were observed. It is theorized This ship, a highly capable satura- the fiber optic cable assembly, and the that these windy conditions could have tion diving vessel, can also deploy the vehicle itself. The fiber optic cable contributed to the fiber optic fault. DOLPHIN 3K as well as other ROVs. consists of two spoolers: one is in the The second trial was in the afterThe KAIYO can be held stationary vehicle and the other is on the ship. noon and the vehicle achieved the design during dive operations by means of a Each contains 1,500 meters of graded depth of 500 meters. An 11-kg dropfour-point mooring or by dynamic index (G.I.) fiber optic cable. Both can weight controlled the descent velocity positioning. While in the dynamic uncoil independently if there is excess (approximately 64 cm/s), and the weight positioning work mode, a computer loading (1 kg tension), and the opera- dropped near the bottom. After a tracking system maintains the ship's tion is similar to an expendable bathy- 45-minute survey at depths from 487 to position from bottom-mounted trans- thermograph (XBT). UROV-500 spec- 501 meters, the vehicle was recovered ponders or land-based systems. Actual ifications are as follows:

without incident. This demonstration movement of the ship is controlled by

confirmed that a self-powered vehicle, bow and aft thrusters and the KAIYO's Depth

500 m

having expendable fiber optics, offers twin screws.

Size

2 (L) x 1 (W) x 1 (H) m significant promise for undersea JAMSTEC has been developing fiber Weight

research applications. optic linked, battery operated, Speed

1 m/s (max)

UROV's salient features of high untethered ROVs since 1986. One of

0.5 m/s (cruise)

quality video and excellent maneuverthese systems, termed the UROV-2,000, Batteries

Ni-Cd, 100 V 20 AH, ability combine to provide a suitable is designed for operations to

24 V 20 AH

platform for visual transects and 2,000 meters and completed successful

2 x 500 W (F/R)

inspections related to various undersea sea trials in 1990 (Ref 4). These tests

2x 250 W (U/D)

tasks. In addition, such a design configdemonstrated the functional ability of Instrumentation ...... CCD color TV, black & uration would provide a much larger a self-powered, expendable, fiber optic

white low-light TV, light lateral capability than conventional based vehicle. The 0.9-mm-diameter

x 3, still camera (36 ROVs and allow excursions into fiber optics were deployed success

exposures), strobe, presently inaccessible environments fully, and data were collected on system

temperature sensor,

such as under-ice regions. Operational performance. A maximum depth of

transponder, radio advantages of the UROV include the 515 meters was reached during seven

transmitter

elimination of heavy duty deck handling dives.

Cable ........ Expendable optical fiber equipment associated with typical largeAn extension of this development

cable, 0.9-mm diameter, diameter ROV umbilical deployments. has been the design and construction

1,500-m long x 2 (vehicle Secondly, operational constraints of the UROV-500, which has a similar

and ship)

associated with flow-induced cable drag configuration but a depth limitation of Transmission Three-wave length typical of long, large diameter ROV 500 meters. This vehicle (see Figure 1)

division multiple optical umbilicals are significantly reduced. will ultimately be used for fisheries

transmission

It should be pointed out that the surveys in the Japan Sea off Fukui

present fiber optic platforms developed Prefecture. Two tests were witnessed The first deployment was interrupted by JAMSTECare also being utilized as on 6 November: the first successful by a fault in the fiber optics. Retrieval testbeds for advanced AUVs. Research deployment reached 300 meters, while was conducted without incident, and is underway on communication and the second achieved a maximum depth the cable was repaired using an optical control methods that will allow the of 501 meters.

fiber fusion splicing machine. An opti- elimination of the fiber optic cable The UROV-500 was developed ina cal time domain reflectometer isolated linking the support ship with the selfcooperative effort between JAMSTEC the break, and it was spliced within powered vehicle. JAMSTEC is develand Sumitomo Heavy Industries and 30 minutes after recovery. The UROV- oping a color video transmission sysSumitomo Electric Industries. The 500 was subsequently redeployed and tem that will be capable of sending one vehicle is self-powered using Ni-Cd reached a 300-meter depth. The video

6 seconds over distances of batteries and an expendable fiber optic quality of the transmitted pictures was cable to transmit video, sensor, and excellent. During launch operations,

frame per

up to 7 km.

Several tests were conducted. A color screen for visual experiments was deployed in 1,250-meter water depths. Various combinations of light levels and distances were verified. Distributions of Calyptogena communities on the seafloor were readily observed at a 10-meter range using lighting from two 500-W halogen bulbs.

[graphic]

SUPER-HARP COLOR
TV CAMERA

JAMSTEC has sponsored development of a low-light-level color video camera for use on the DOLPHIN 3K. The camera uses three camera tubes that were designed by NHK Science and Technical Research Laboratories. This camera is termed a Super-HARP camera (High-Gain Avalanche Rushing Amorphous Photoconductor). It is theoretically 100 times as sensitive as conventional tubes; this allows not only ultra high sensitivity but also excellent picture quality, low noise, high resolution, low photoconductive lag, and no burning (Ref 5). The specifications of the Super-HARP camera are as follows:

Figure 1. Deployment of UROV-500.

Horizontal resolution > 600 lines DOLPHIN 3K DESCRIPTION manipulator, conductivity/temperaturel Minimum luminous AND ASSESSMENT depth (CTD) sensors, and various intensity

..... 0.8 lux (9 dB up) sampling containers and tools (Ref 1). S/N ratio

>60 dB The DOLPHIN 3K ROV (Figure 2) The ROV is designed so that it can Outer diameter & length $ 184 x 632 mm is a 3,300-meter-deep vehicle designed be deployed offeither the R/V KAIYO Operational depth

>3,300 m for undersea science applications, espe- or the RN NATSUSHIMA. Another cially marine geological. The DOLPHIN application of the DOLPHIN 3K ROV Another purpose of this assessment 3K was designed and developed by Mitsui is to serve as the rescue vehicle for the was to observe the undersea science Engineering and Shipbuilding Co., Ltd. submersible SHINKAI 2000 that is capabilities of the DOLPHIN ROV. (MES) for JAMSTEC. It has been uti- operated by JAMSTEC. The ROV The ROV was efficiently deployed and lized since 1987 for various scientific also has been used for predive surveys retrieved using the A-frame on the stern applications to depths of 3,429 meters. in support of the SHINKAI 2000. of the NATSUSHIMA. The ROV

Major shipboard components The DOLPHIN 3K was installed on performed video and photo survey traninclude a control/navigation van, a deck the R/V NATSUSHIMA for test dives sects 1 to 5 meters off the seafloor and handling system including a heave on 7 November, also near Hatsushima collected approximately 20 clams using compensator, and a winch for the Island, for the purpose of evaluating a the manipulator and a wire mesh scoop. 5,000-meter-long, 30-mm-diameter high-resolution, low-light-level TV The clams were placed in an insulated ROV umbilical. ROV capabilities camera. In addition, samples of giant container for further study. This same include broadcast quality TV video via clams (Calyptogena) were observed and site has been surveyed extensively over optical fiber cable, master-slave seven- recovered by the ROV sampling and the past several years using the ROV, function manipulator, a five-function collecting equipment.

and there are several long-term experiments underway on the seafloor.

[graphic]

CONCLUSIONS

Both the UROV-500 and the DOLPHIN 3K ROV performed well during the operations observed. The UROV design, which combines fiber optic technology and onboard power, eliminated problems associated with long, bulky umbilicals. It is envisioned that various mission-specific fiber optic type vehicles will be developed in response to science needs, will be relatively low cost, and will operate in areas inaccessible to manned submersibles, i.e., under ice environments. This design configuration allows for large lateral excursions that are unattainable using conventional ROVs. Planned elimination of the fiber optic link over the next few years will provide autonomy to the design but will likely increase costs and complexity.

The DOLPHIN 3K is an excellent undersea research platform and is a valuable supplement or, in some cases, replacement to manned submersible operations. With a depth rating of over 3,000 meters combined with sampling capability, excellent video, CTD, and sonars, the DOLPHIN 3K has numerous salient features for undersea research applications. The newly developed Super-HARP low-light-level TV camera provided excellent color picture quality and high resolution under various lighting conditions. Superior visual acuity is an important criterion for

Figure 2. DOLPHIN 3K ROV. unmanned platform science operations.

A major advantage of the SuperHARP TV camera is the field of view, Moreover, if a low-light-level camera of the seafloor macrostructure using both width and depth, that the camera is used, the resolution and picture quality the video images. provides without a requirement for large are degraded. Immediate applications Beyond this initial application, the separation of the camera and lighting of the Super-HARP camera at uses for the Super-HARP camera are to minimize backscatter. Prior to the JAMSTEC will be to map the hypo- virtually unlimited. The ability to seeat development of this system, underwater thermal vent fields near the Okinawa greater distances, at a wide field of TV cameras required high intensity lights Trough. In the past, it has been difficult view, and at a suitably high resolution that sometimes resulted in a narrow to identify and navigate this complex will aid all disciplines of undersea field of view and distracting backscat- field of “chimneys”; the Super-HARP research conducted from unmanned and ter from suspended particulate matter. camera will allow the detailed mapping manned platforms.

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