Newsgroups: comp.robotics
Path: brunix!cat.cis.Brown.EDU!agate!ames!kronos.arc.nasa.gov!doctor
From: doctor@kronos.arc.nasa.gov (Terry Fong)
Subject: Dante II - Mt. Spurr Expedition Status (29-Jul-94)
Message-ID: <1994Jul31.081928.28685@ptolemy-ethernet.arc.nasa.gov>
Summary: status information on CMU/NASA volcano robot explorer
Keywords: Dante, teleoperations, volcano, Alaska
Sender: usenet@ptolemy-ethernet.arc.nasa.gov (usenet@ptolemy.arc.nasa.gov)
Nntp-Posting-Host: tardis.arc.nasa.gov
Organization: NASA Ames Intelligent Mechanisms Group
Date: Sun, 31 Jul 1994 08:19:28 GMT
Lines: 134

The following is a status update on the Dante II project. Dante II is
an eight-legged robot (developed by the CMU Robotics Institute with
sponsorship from NASA) which is currently descending into the active
crater of Mt. Spurr, an Alaskan volcano 80 miles west of Anchorage,
Alaska. The primary objective of the Dante II project is to develop and
evaluate new techniques and technologies which can be applied to space
and planetary exploration. 

Throughout the Mt. Spurr expedition, Dante II is being remotely
operated from a base station in Anchorage using control station
software developed at CMU and NASA Ames. Live video coverage is
periodically available via NASA Select. Full mission details including
current status, real-time images/video, and technical data is available
via a WorldWideWeb server provided by the NASA Ames Intelligent
Mechanisms Group. This site can be accessed on the Internet using
information browsers such as NCSA Mosaic and the URL:

	http://maas-neotek.arc.nasa.gov/dante

Questions regarding the Dante II project may be addressed to me via email 
(terry@ptolemy.arc.nasa.gov). Reponse time may be slow.

Terry Fong
NASA Ames Research Center

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Daily Report (29-Jul-1994)

Today's report will be fairly short and to the point (it has been a
very long day and there was not an opportunity to start writing this
until very late).  After closing out the issues identified during
yesterday's vehicle checkout, Dante is now up and walking, and on it's
way into the crater!

After flying out to the crater rim in the morning, Scott Boehmke
(Dante communications engineer), David Wettergreen (Dante software
architect) and Ryan Miller (Dante electronics engineer) began the work
to examine and seal the leaky actuator housing, replace the faulty
load cell and correct the communications problems.  They were joined
mid-morning by John Bares (project manager) and Dimi Apostolopoulos
(Dante mechanical engineer).

After an initial inspection and test to verify that all enclosed
systems were still functioning properly after yesterday's drying
effort, the vertical actuator housing for the #2 leg was sealed and
RTV'd in place.  The load cell for the leg was then replaced and
tested, and then the communications problem was addressed.  It was
determined that rather than replacing the Tutankhamen communications
board, an alternate method of guaranteeing signal strength could be
implemented.

The tether which supports the weight of the robot on steep and
vertical slopes also contains a number of power and signal conductors
inside the sheath of the cable, including the network twisted pair
lines connected to the Tutankhamen.  By using an additional set of
twisted-pair conductors in the cable to connect the boards at either
end of the tether, a redundant signal path was established which also
resulted in a lower overall resistance to the signal lines.  As a
result, the line noise and signal degradation problems virtually
disappeared from the network communications, and Dante was up and
running (er, I meant "up and walking").

The next hour was spent carefully walking the robot off the transport
pallet and onto the snow field in front of the robot.  At 2:30pm ADT,
Dante was off the pallet and was beginning to walk on the crater
slope.  The first exercise was a 30-degree left turn to face the robot
downhill.  Initially, progress was intentionally kept to an extremely
slow pace so the operators could gather characterization data on the
performance of the robot and it's subsystems.  Of particular interest
was how the robot was behaving as it walked through the deep snow
which covered the first 100 feet of the descent.

When the robot first walked off the pallet, the parameters for the
control software were set for a walking surface with high strength and
high density (ie.  concrete or very hard packed dirt).  When walking
on snow with these setting, Dante displayed a jerky "bounce and
settle, bounce and settle" motion when placing each four leg frame as
it walked.  By experimenting with the forces exerted by the legs as
they came in contact with the snow surface, Henning Pangels (Dante
control software engineer, and Dante's "driver" for today) was able to
smooth the walking of Dante.  The robot was adjusted so that
sufficient force was applied downward as each leg came in contact with
the snow surface to compress the snow to support the weight of the
robot without a secondary compression (which was causing the bouncing
seen earlier in the day).  This modification, in conjunction with the
snowshoes added to the legs of the robot, provided a very stable
support foundation for the robot as it walked down the crater.

By the end of the day, Dante had walked over 100 feet from the pallet
down to the ridge near the rim station, which is five times the
distance walked by the first iteration of Dante in Mt. Erebus last
year.  The performance of the robot in snow was recorded and
characterized, and the team also had an opportunity to examine how
well Dante walked through the deep volcanic mud along the ridge near
the rim station.  Once at the ridge, the robot was stopped for the
evening and the anchor point on the tether was relocated (this was a
planned activity, which is intended to provide additional length of
tether for the robot to permit extended excursions into the fumerole
fields at the bottom of the crater if an appropriate area of interest
is identified).

At the end of the anchor relocation the team members on the rim
departed to head back to Anchorage.  If all goes well and there are no
new hardware failures, the team will not return to the rim of the
volcano until Dante has completed the excursion to the bottom of the
crater and returns to the rim in approximately five days.

As each of the day's activities was completed, the project team
members at Ames Research Center (who are providing the VEVI software
and NSI communications) continually updated the Mosaic page for the
project which is being maintained on the World Wide Web
(http://maas-neotek.arc.nasa.gov/dante/dante.html).  Over 500 visits
to the page were recorded in just the few hours that the robot was
walking, during which images from the robot cameras were frequently
captured and posted on the page along with progress updates and mpeg
movies of the robot's first steps.

As a closing note, the helicopter crash on Mt. Spurr should be
mentioned.  Late in the afternoon, a tourist helicopter flying near
the summit crashed at the 10,500-foot level of the mountain with five
people aboard.  Radio communication later revealed two injured and
three "just shaken up" flyers, who were rescued by the Alaska National
Guard and flown to Anchorage.  Early media inquiries to the contrary,
none of those aboard were associated with the Dante project
Nonetheless, we would like to wish for a speedy recovery for those injured in 
the crash, and hope that they are faring well.

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-- 
_______________________________________________________________________________
 "Every once in a while declare        Terry Fong <terry@ptolemy.arc.nasa.gov>
  peace. It confuses the hell out      NASA Ames, M/S 269-3, Moffett Field, CA
  of your enemies" -- Rule of Acq. #76      (415) 604-6063, (415) 604-6081 lab
