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 (31-Jul-94)
Message-ID: <1994Aug1.144558.22766@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: Mon, 1 Aug 1994 14:45:58 GMT
Lines: 139

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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Status Report (31-Jul-94)

At the conclusion of a 13-hour day of walking in the volcano, Dante now
is resting approximately 550 feet into the crater, and is approximately
140 feet from the area of primary science interest.  During the day, the
robot crossed some of the most rugged and hazardous terrain it has ever
encountered, either in the crater or in practice.  As the day's
operations were completed, Dante had traversed down to the upper end of
the 100-foot long green rock bulge which hangs above the fumerole field
at the bottom of the crater, and the fumeroles were clearly visible
through the on-board cameras.

To reach this point, the robot departed from the "parking place" below a
protective boulder where walking was concluded last evening, and
descended along the north side of a ridge line for about 100 feet.
During this portion of the descent, Dante's operators (Henning Pangels
and Dave Wettergreen, who were supported all day by backup "drivers"
Dimi Apostolopoulos and Murali Krishna) again enabled the behavior-based
walking ability of the robot which basically allows the robot to control
it's own motion and walk under a high degree of autonomy.  This type of
operation maximizes the onboard "intelligence" of the robot while
minimizing the requirement for constant human oversight of the walking
process.  By using information from the force and torque sensors in the
legs of the robot, combined with input from sensors which determine the
attitude and orientation of the body of the robot, Dante "gropes" across
the terrain feeling for hazards and obstacles which might impede it's
path.  Demonstrating that this type of operation, in which the operator
merely specifies the pattern and direction of the walking to be
performed and then allows the machine to complete the task, can
successfully operate in this harsh environment was one of the principle
technical objectives of the project.

As the robot walked off the ridge after the first 100 feet of activity,
the operators conferred to select the next portion of the descent route.
Working only from the on-board camera views and a single overhead
photograph taken during the reconnaissance flight nearly three weeks
ago, they attempted to determine the most likely descent path to reach
the science goal areas.  One of the things learned during this and
similar prior discussions is the difficulty of obtaining a complete
understanding of the topology of an area of unknown terrain using just
this limited set of viewpoints.  And in this case, the task is made even
more difficult due to the fact that significant snow melt has occurred
since the single overhead photo was taken and the terrainability of the
exposed surfaces in the crater has changed considerably (which makes
correlation of the camera views with the overhead view to determine the
current position of the robot very difficult).  Yet the team is
intentionally restricting the viewing information to just these sources
in an effort to have the project be analogous to a lunar or planetary
rover mission which would have similar viewing limitations (ie. only
onboard cameras and perhaps a series of long-range overhead views from
an orbiting platform, and no positioning tools such as GPS).

As a result, the team has confirmed the belief in the enormous value of
the onboard laser scanner and topology mapping system which allows the
robot to scan the terrain and generate a computer model of the local
topography.  In several cases during the descent (including two times
today), the operators have placed more reliance on the scanner-generated
terrain model than the video and photographics information to get a real
understanding of the local slopes and hazards around the robot as they
planned the high-level course to the bottom of the crater.

At the end of the day Dante had walked down into a wide gully at the top
of the green rock bulge which offered relatively hazard-free terrain.
However, the bottom of the gully appears to be impassible, blocked by
very large boulders near the base of the rock bulge.  The robot was
parked for the night next to the north escarpment of the the gully, and
the first activity for the morning will be to move up the escarpment and
walk parallel to the gully for the next portion of the descent.

At this point in the descent, data regarding the performance and
characterization of the robotic technologies onboard the robot has been
gathered, and sufficient information has been collected to significantly
increase the fundamental knowledge about exploration robotics in extreme
field environments.  However, the goals of reaching the bottom of the
crater and returning information about the crater environment to the
Alaska Volcano Observatory scientists have yet to be achieved.  If all
goes well, tomorrow's traverse may conclude with the robot in the
proximity of the upper fumeroles.  Reaching this point to take gas
concentration observations with the onboard sensing package, and
transmitting views of the unknown area below the rock bulge back to the
operators, would complete the primary science goals of the project.

During the entire day the crater was once again bombarded by rock fall
from the walls hanging above Dante's descent path. On several occasions,
the sounds of large rock slides could be heard though the microphone
mounted on the rim camera.  At one point during the middle of the day, a
one-meter diameter boulder sailed by the back of Dante, passing just
under the tether which was suspended between the robot and the ridge
crossed late yesterday.  This matched the larger boulder which rolled in
front of robot yesterday afternoon, after having peeled off the northern
wall nearly 600 feet above.  Either one of these rocks would have likely
destroyed Dante had it collided with the robot or the tether (with one
falling rock in front and the next one passing just behind, it seems
like the mountain is establishing the range of the robot, and the next
one may be dead-center...).

For those that are interested, live video from the robot cameras is
being carried by NASA Select television from 10:00am ADT to 10:00pm ADT
(2:00pm EDT to 2:00am EDT) during the remainder of the project, with
hourly status updates.  NASA Select is provided by many local cable TV
companies, and can also be acquired by those with access to a satellite
dish (on Spacenet II, at 69 degrees west, 3880 MHz, transponder 5,
channel 9).  As previously mentioned, status updates, captured
photographs and compressed video are also being provided on the project
Mosaic home page at "http://maas-neotek.arc.nasa.gov/dante/ dante.html".

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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
