From: roberts@CMR.NCSL.NIST.GOV (John Roberts)
Newsgroups: sci.space
Subject: Notes from Rover Expo
Date: 5 Sep 92 04:26:23 GMT
Organization: National Institute of Standards and Technology
	formerly National Bureau of Standards


On Wednesday, I went to the September 1-2 planetary Rover Expo that was
described in sci.space and sci.space.news. It was extremely interesting.
All of the rovers were on display, and they took turns moving about on a
simulated martian terrain (large rocks and local clay soil mixed with
pigment to give it the vivid orange color of martian soil). There was also
a smooth runway between the simulated terrain and the audience, with a
considerable number of small children allowed to sit along the runway, and the 
smaller rovers were moved along the runway so the kids could see them up
close. (Naturally the rovers tracked a lot of the colored soil onto the
runway, and the kids rolled in the dust and quickly spread it to the bleachers
and everywhere else in the tent - few people escaped getting Mars-colored.)
A running commentary was given with each demonstration, often with the same
person talking and controlling the rover.

The main sponsors of the Rover Expo were NASA, the National Air and Space
Museum (which had a sign inside the door of the museum), and the Planetary
Society. Co-sponsors included the Russian Mobile Vehicle Engineering Institute,
the Centre National d'Etudes Spatiales, and the Space Automation and Robotics
Technical Committee of the American Institute of Aeronautics and Astronautics.

>From the literature, here are the rovers that participated, and the 
organizations that provided them, with some comments by me:

..............

Babakin Center
 NPO Lavochkin, Moscow
Space Research Institute
 Russian Academy of Sciences
Mobile Vehicle Engineering Institute
 (VNIITransMash)

  - Unnamed Marsokhod (Mars Rover)
    size: 1.2 x 1.0 x 0.8 meters
    mass: 75 kg
    speed: 10 cm/s
    comments: Rover will be named in an international student contest.
      Three pairs of long, tapered wheels with small blades. "Wheel mode"
      can handle slopes of 20 degrees, "wheel-crawler mode" 30-35 degrees in
      loose soil. Largest individual stones 0.5 m. Service life 100km. Can
      be commanded directly from orbiter for use in dangerous conditions,
      programmed mode for motion along a specified route, and autonomous mode
      for motion in a given direction, with route corrections. Returns
      high-resolution color stereo images of surface, also has numerous
      scientific instruments. Scheduled for a demo. Tested in the Mojave Desert
      with the aid of the Planetary Society.

      Also shown was a "hot air balloon" to represent the SNAKE instrument
      (dragged along the Martian surface by a balloon) developed by the
      Space Dynamics Laboratory (Utah State University), JPL, the French
      space agency CNES, and the Planetary Society, and scheduled to be
      launched on a CIS Proton booster in 1996.

..............

Carnegie Mellon University
 Robotics Institute
 Pittsburgh, Pennsylvania

  - Ambler
    size: 4.5 x 3.0 x 5.5 meters
    mass: 3 tons
    speed: 0.8 cm/s
    comments: The six-legged walker that Marc Ringuette has described. It's
      been operational for a year or more - I've seen it on CNN and NASA
      Select. It's really enormous, and apparently is quite a job to control -
      there was a battery of computer workstations set up to do it. Apparently
      the last demo Tuesday was to walk the Ambler out onto the terrain, and
      the first demo Wednesday was to walk it back to its resting place.
      Able to step over objects 1 meter high, and maintain a level body on
      a 30-degree slope. Laser rangefinder on top of body. There are plans
      to give the Ambler considerable autonomy. (This should largely make
      up for the low speed, for use on Mars.)

  - Dante -- the Erebus Explorer
    size: 3.0 x 1.9 x 3.5 meters
    mass: 400 kg
    speed: 2 cm/s
    comments: Another (6-legged?) walker, hard to describe. It appears to
      be made of beautiful purple anodized aluminum. It's intended to explore
      the active volcano Mount Erebus in Antarctica in 1992. Another robot,
      Virgil, also called the transporter, is to ascend to the rim of the 
      crater, where it will lower Dante, also called the rappeller, to observe 
      the lava lake, measure temperatures, take samples, etc. Not scheduled
      for a demo. Cameras return anaglyph stereo display.

..............

IS Robotics
 Cambridge, Massachusetts

  - Attila II
    size: 38 x 25 x 30 cm
    mass: 3 kg
    speed: 5 cm/s
    comments: No other information. Apparently it was not scheduled for a demo.

  - Genghis II
    size: 38 x 25 x 20 cm
    mass: 1.7 kg
    speed: 10 cm/s
    comments: Was scheduled for a demo. A 6-legged walker.

  - T-1
    size: 38 x 45 x 25 cm
    mass: 6 kg
    speed: 30 cm/s
    comments: Was scheduled for a demo. Looks like a wheeled vehicle in the
      photograph, but hard to tell.

  - Treader
    size: 45 x 35 x 35 cm
    mass: 4 kg
    speed: 30 cm/s
    comments: Was scheduled for a demo.

..............

Jet Propulsion Laboratory
 Robotic Systems & Advanced Computing Technology Section
 Pasadena, California

  - Rocky III
    size: 80 x 80 x 80 cm (JPL literature says 60 cm long by 45 cm wide.)
    mass: 8 kg (JPL literature says 15 kg, which seems more likely.)
    speed: 10 cm/s
    comments: Six-wheeled design with articulated, "rocker-bogie" suspension
      to allow it to climb over objects 1.3 times as high as wheel diameter.
      Wheel encoders, bumpers, articulation sensors, magnetic compass, and
      attitude sensors. Developed for autonomous sample-acquisition experiment
      using computerized navigation system called "behavior control". User
      determines location of interest - rover travels to that location
      autonomously, scoops up a soil sample, and returns it to the lander,
      following an infrared beacon as a homing device. Large obstacles are
      avoided. I saw a demo of Rocky III.

  - Rocky IV (not present at show)
    size: 60 cm long by 45 cm wide
    mass: 7.2 kg
    speed: ?
    comments: Interest in use as Mars Environmental Survey Pathfinder.
      Same basic design as Rocky III. Deploys microseismometers, scoops
      soil samples, and chips rock surfaces. This is the model that uses
      stereo cameras with alternate-field liquid crystal shutter goggles
      for the operators. I spoke with the JPL people, and they said they're
      using standard NTSC format, 30 frames per second. Onboard spectrometer.

  - Go-For (pronounced gopher)
    size: 50 x 50 x 50 cm (actual volume is very small)
    mass: 3 kg
    speed: 30 cm/s
    comments: This is the weird little yellow rover that looks sort of like
      a dog (named Rover, no doubt) without the head. It has four wheels,
      mounted on the ends of front and rear forks. The forks can be pivoted,
      which helps greatly with maneuverability. Normally, the forks are
      adjusted so that 80% or more of the body weight is on the rear wheels,
      which allows the front wheels to climb over obstacles as high as 70%
      of the length of the rover. The forks can be stretched out straight
      to allow the rover to lie flat, and the body can be tilted forward to
      get extreme close-ups of rocks or soil using a front-mounted camera.
      It can also drop microseismometers out the back, though it will only
      be allowed to do this in the pet exercise area. :-) If a maneuver
      is miscalculated and Go-For tumbles over on its back, the forks can be
      pivoted to turn it rightside-up again. (Few if any of the other rovers
      shown have the capability to right themselves, so they have to have
      safety systems to stop motion if they start to become unstable.)

      I saw Go-For operated twice, once while Rocky III was still running,
      and once while Robby was being demonstrated (they had to be careful
      to prevent Robby from running over Go-For). It worked very well,
      and successfully recovered from a tumble. Go-For was a great favorite
      with the kids, who mauled it mercilessly. It survived that, so I guess
      it should do pretty well in the less hostile environment of Mars. :-)

  - Robby
    size: 4 x 2 x 2.5 meters
    mass: 1.8 tons
    speed: 1 meter/s
    comments: Six 35-inch diameter wheels on a pivoting 3-part body, to allow
      it to go over obstacles about 3 feet high. It has four video cameras
      on a pivoting bar up top, and a robot arm in front. The camera bar
      sweeps up, down, and side to side as Robby maneuvers. It also has 
      a gyrocompass and attitude and articulation sensors. Robby scans
      the terrain with its black-and-white stereo cameras, then plans and
      executes a safe path. Autonomous navigation at the rate of 80 meters
      per hour has been demonstrated.

      During the demo, Robby was kept well away from the kids, so none of
      them were run over.

..............

Martin Marietta Corporation
 Astronautics Group
 Denver, Colorado

  - Beam Walker
    size: 1.5 x 1.5 x 1.2 meters
    mass: 160 kg
    speed: 3 cm/s
    comments: There are two sets of legs, which can move straight up and down
      either individually (I think) or together in sets. The outer set consists
      of two legs in front and one in back, mounted to the main frame of the 
      rover. The inner set is made up of four legs in a square configuration,
      mounted to an inner frame. In normal operation, the inner frame goes
      down, lifting the three outer legs off the ground. The inner frame 
      then glides backward relative to the rover body, causing the body
      to move forward relative to the ground. The inner frame then moves up,
      raising the inner legs off the ground and causing the rover to rest
      on the outer legs. In this position the inner frame then glides forward
      relative to the rover body, and the cycle repeats. Steering is 
      accomplished by rotating the inner frame while its legs are holding
      up the rover. I saw the demo.

..............

Massachusetts Institute of Technology and Charles Stark Draper Laboratory
 Cambridge, Massachusetts

  - MITy
    size: 53 x 34 x 35 cm
    mass: 10 kg
    speed: 45 cm/s
    comments: Scheduled for a demo.

..............

National Institute of Standards and Technology (hey, that's us!)
 Robotic Systems Division
 Bethesda, Maryland (didn't even know about the Bethesda site - I know
   there's some robotic work done at the Gaithersburg site - mainly computer
   control of advanced industrial robots, but also other projects such as the
   Flight Telerobotic Server (?) )

  - Spider
    size: 3.7 x 3.7 x 3.7 meters
    mass: 18 kg (very open framework)
    speed: 2.25 meters/s
    comments: It turned out that one of the people exhibiting it was an old
      friend from high school, who explained how it works. NIST has been
      working on a revolutionary type of crane, which consists of a batch of
      long poles connected to the ground at three anchor points, plus six 
      winches and cables, running through pulleys to a triangular central
      platform, where the crane equipment is attached. This structure is
      useful because of its stability, and because it can lift many times its
      own mass. Somebody apparently figured out that you could attach tractor
      treads in place of the ground anchor points with sophisticated angle
      detection sensors, add a long boom to the top with stereo cameras
      on the end, and make the crane into a rover. I was there for the
      second demo, but the control computer had blown out. However, there
      was a videotape showing it in operation. I still don't understand
      exactly how it works.

..............

Sandia National Laboratories
 Advanced Vehicle Systems
 Albuquerque, New Mexico

  - Dixie
    size: 1.6 x 1.0 x 1.0 meters
    mass: 180 kg
    speed: 13.5 meters/s
  - Raybot
    size: 1.9 x 1.0 x 1.0 meters
    mass: 180 kg
    speed: 11.25 meters/s
    comments: Dixie and Raybot are apparently converted small 3-4 wheel
      all-terrain vehicles (including the gasoline engines, though I didn't
      see them in operation - presumably a planetary version would have a
      different power source). Dixie and Raybot are designed to be used
      together, controlled from a single Command Driving Console (CDC).
      Raybot is similar to Dixie, but includes an advanced multiprocessor
      control architecture and an articulated arm at the rear of the robot.

      Dixie is driven out to an overlook position, from which it provides
      a wide-field stereo image to be used for analysis and planning.
      Dixie is then put into a safe state, with ignition [!] off and the
      parking brake set, and the operator switches control from Dixie to
      Raybot. Raybot is moved to a specified location within the field of
      view of Dixie, and the robot arm and scientific equipment used.
      Control may be switched back and forth between the two rovers to
      change their positions.

      Dixie and Raybot were scheduled to be demonstrated together.

  - Ratler
    size: 60 x 60 x 46 cm
    mass: 15 kg
    speed: 10 cm/s
    comments: Scheduled to be demonstrated.

..............

General comments:

 - Most (but not all) of the rovers described are intended to have some 
   degree of autonomy in their final application. In the live demos, I
   think most of these were more directly controlled than would be the case
   in normal use. As one speaker put it, these demos were intended mainly
   to show the mechanical capability of the rovers - in many cases, autonomous
   control systems are not yet fully functional. There was also the matter of
   controlling the rovers in the limited environment of a tent with people
   in it - even Robby, which has demonstrated autonomous operation, was
   probably pretty closely monitored to keep it from damaging the set or
   hitting the spectators.

 - According to one speaker, the typical maximum slope most of the rovers can
   negotiate in loose soil is around 30 degrees, because of the physics
   involved.

 - Many of the speakers were optimistic about getting their rovers into
   off-earth use within the decade.

 - A lot of the information in the comments above is from literature that
   was available at the show. Not all the booths had literature, but I
   was there late on the second day, so there may have been more at the
   beginning. JPL had nice big color photos of all four of their rovers.

 - For the most part, the representatives were very informative and helpful.
   I was impressed by the heavy involvement of the Planetary Society. (Of
   course, this is probably the one technical thing that they do really well.)
   I'll have to watch the NASA Select tape I got of their Case for Mars
   conference, and decide once again whether I want to sign up. I get
   some impression that they're slightly more technical and less political
   than in the past. At least, the fact that they're supporting rovers to
   Mars before humans is encouraging (since it's something the space program
   can afford now).

 - I've tried to double check all the information, but there could still be
   errors.

 - I was only there a few hours of one day, so I only saw a few of the rovers
   in operation. However, I got some good 3D video (same format as JPL uses)
   of those demos, plus the rest of the rovers on display. When I review the
   video, if I come up with any additional information or corrections, I'll
   try to post.

Overall, I'd say the Rover Expo was very interesting, and was very well
attended.

John Roberts
roberts@cmr.ncsl.nist.gov

Newsgroups: sci.space