Newsgroups: comp.robotics
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From: doctor@kronos.arc.nasa.gov (Terry Fong)
Subject: NASA Ames Antarctica TROV Project Status (10/25/93)
Message-ID: <1993Oct26.001043.29233@kronos.arc.nasa.gov>
Summary: status information for virtual environment teleoperations project
Keywords: virtual environments, teleoperations, Antarctica
Sender: usenet@kronos.arc.nasa.gov (usenet@ptolemy.arc.nasa.gov)
Nntp-Posting-Host: tardis.arc.nasa.gov
Organization: NASA Ames Research Center (Intelligent Mechanisms Group)
Date: Tue, 26 Oct 1993 00:10:43 GMT
Lines: 144

The following is a status update on the NASA Ames Antarctica
Telepresence Remotely Operated Vehicle (TROV) Project. The principle
objective of the project is to assess the capabilities of telepresence
and virtual environments for performing remote scientific field work.
Throughout the project's duration (10/5-12/2), an underwater telerobotic
vehicle is being operated under McMurdo Sound, Antarctica from a
control station located at NASA Ames (Moffett Field, CA).
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(extracted from reports sent by Dr. Carol Stoker, field team leader)

This past week has been devoted to set up and verification of the TROV
and telecommunications system. Last week, the TROV equipment was
set up and tested to verify that it had survived the shipment to
Antarctica. This testing was performed in the lower level of the
Crary Science Building in McMurdo.

On Saturday, Oct. 16 , the "Hypertat" operations hut was delivered to
the "transition zone"--the interface between the sea ice and the beach
front of McMurdo Station. The Hypertat is an A-frame structure with 6
large windows and 4 smaller porthole style windows. It is bright
orange with white trim.  From a distance it looks like a red barn.
One side of the Hypertat contains a long work bench which proved
perfect for holding equipment racks and monitors.  On one end is a
"Preway" propane heater and on the other is a large freezer door.
Freezer doors are the preferred type of door structure in Antarctica
because of their insulation value and secure closure.  The Preway
heater keeps the building very warm,. in fact it can be uncomfortably
hot especially when wearing warm clothing required for working
outside. In the center of the Hypertat, on the floor, is a large trap
door through which the TROV is deployed. The exterior of the Hypertat
also has solar electric panels which provide enough electrical power
to run some essential equipment 24 hours a day, without requiring
tending. The Hypertat was also outfitted with a Ritron radio
telephone to which an international phone line was installed to
provide us with voice communications with our teammates in
California.

On Saturday (10/16) the equipment was packed up and moved into the
Hypertat out on the sea ice.  Most equipment was moved using a
standard 4WD pickup truck, but the TROV and its umbilical (both boxes
weighing over 500 lbs) were carried down to the ice in the bucket of a
bulldozer.  The bulldozer was moving snow away from the loading dock
near the area where the equipment was being tested.  We had to wait
for him to clear away several tons of snow which had been shoveled
into the driveway of this dock, and he offered to move the big boxes
using the dozer bucket, saving us all a lot of backstrain.

On Monday morning Oct. 18, "T-Rex", a large Nodwell tracked vehicle, the
workhorses of the Antarctic,  met us at the transition zone to move our hut
into the first site of interest.  This was an area in Winter Quarters Bay
which is the site of several of the public works facilities, including the
waste water effluent outfall, and the Ice Pier.  In late fall, after the
sea ice has broken out of McMurdo bay, ships come in to bring supplies to
the station to last the winter.  The pier for the ships is made of fresh
water ice, which melts at a higher temperature than sea water ice and thus
remains solid even though the sea ice has melted.   T-Rex towed the
Hypertat over to the site, drilled a 4' diameter hole in the sea ice, and
positioned the Hypertat properly over the hole. 

In addition to equipment loaded into the Hypertat hut, we had arranged to
use a trailer on skis to haul around the external equipment such as the
TROV umbilical cable, the generators, extension cords, extra cabling, Jiffy
Drill and other miscelaneous equipment.  We were also issued a "Sprite"
tracked vehicle for travel around on the sea ice.  Our Sprite, number 666
and called the "anti-sprite",  is roughly the size of a pickup truck.  It
is fire engine red with bucket front seats and a cargo compartment in the
back.  It has an onboard radio over which we check in and out of a central
radio clearing house called "Mac Ops" every time we move onto the sea ice. 
This is a safety precaution required of all vehicles operating on the sea
ice. 

Once stationed out on the sea ice, we set up the Hypertat to be our
home for the next seven weeks.  The first set up required plugging
together the complicated set of computers, electronics, video monitors
and TROV controllers in a final configuration.  A microwave laser
transmitter was mounted on a tripod and placed outside the hut.  This
transmitter is used for sending the video signal from the TROV to a
matched receiver mounted on the roof of the two-story firehouse
building in the center of McMurdo.  The receiver, also mounted on a
tripod, was placed on the roof of the firehouse approximately 1
kilometer away from the field site.  The transmitter and receiver pair
must be precisely pointed at each other, a delicate job requiring
binoculars, patience and balance especially when on the sloping
corrugated metal roof of the firehouse in the wind and cold.  A remote
ethernet link (microwave bridge) between the hut and the firehouse is
accomplished using matched Yagi antennas mounted on the roof of the
hut and on the roof of the firehouse. These antennas must also be
properly aligned after each move of the hut. Once video and ethernet
are received at the firehouse, they are sent via microwave to Black
Island and from there via satellite to a ground station in Vallejo,
California (30 miles NE of San Francisco), where they are relayed via
land lines to NASA Ames.

Transponders for the Sharps navigation system were deployed through
holes drilled in the sea ice, currently about 2 meters thick, using a
Jiffy Drill.  After drilling the holes, the three transponders were
lowered 15 meters down the holes.  For surveys in deeper water,
the transponders will be lowered down to 100 m depth.  The navigation
system is capable of locating the position of the TROV, inside the
network of the transponders, to an accuracy of 2 cm.  In turn, the
locations of the transponder grid holes will be surveyed so that the
entire survey area, and all the video footage taken in it, will be
registered in latitude-longitude coordinates.

After all the equipment was fully set up and installed, which took several
days of the week, we were finally able to test out the entire end-to-end
system.  This included sending video and data to Ames, and receiving
command signals for control of the TROV from Ames.  While most of these
capabilities had been tested under some sort of simulated conditions, they
could not be tested under actual conditions until we had all the equipment
set up in Antarctica.  A demonstration of all TROV local and remote control
capabilities was accomplished by the end of the week. 

On Saturday Oct. 23, the now operational system was again picked up by T
Rex and towed to the first scientific survey site in Cape Armitage.  The
hut was positioned over an area which has been the site of an ecological
study performed using traditional scuba diver methods over the last two
decades.  Our plan for the next two weeks is to revisit and resurvey this
area with the TROV, and then to extend the survey into a deeper water area
which has not been previously studied because it can't be accessed by scuba
divers. The TROV will be operated on alternate days either by remote
control from NASA Ames, or by local control from Antarctica.  This will
help us to compare the capabilities and performance issues of operating the
equipment remotely from Ames with the aid of telepresence and
virtual environment technology with local operation of the TROV from
Antarctica (without these capabilities but with the additional understanding
of the environment provided by being here).

The weather as of the time of this writing is a balmy +10F with little
wind.  This is a shirtsleeve day which gives us hope that summer has
finally arrived. 

------------------------------------------------------------------------------
Questions regarding the TROV project may be addressed to me via email 
(terry@ptolemy.arc.nasa.gov). Please excuse any sluggish response since I
am involved daily in project operations.

Terry Fong
NASA Ames Research Center
-- 
_______________________________________________________________________________
 "You do not understand anything       Terry Fong <terry@ptolemy.arc.nasa.gov>
  until you understand it in more      NASA Ames, M/S 269-3, Moffett Field, CA
  than one way..." -- Marvin Minsky         (415) 604-6063, (415) 604-6081 lab
