[chbot] Sumo Practice

[Richard Jones]

Andrew asked how the practice session went, sorry its taken until now to
reply.

Nine people attended. We started a little late as the Seminar Room door was
locked and although I had access to the corridor we could not get into the
main room. The nice security guy turned up at about 6.35 and we went in.

Stuart, William, Scot and Tiffany brought along their NXT creation
subsequently named Topple. Topple is a first generation Lego Sumo bot that
had not seen active service or even a Sumo ring until the evening. Of
course thats what the practice session was all about. Topple had a tendency
to advance to the edge of the ring and fall off as it tried to reverse to
the centre. Its a nice little twist raising the ring a few cm off the
floor! When spinning on the spot looking for prey Topple had a tendency to
scratch circles in the black paint of the sumo ring. Some quick rebuilding
to add a caster, modify the centre of gravity and new software reduced the
wear on the once new sumo ring and battle commenced. To be fair Topple was
up against Gnasher, a second generation bot with many incremental
improvements along the way, so Topple retired having fought bravely but not
very successfully.

Vilna had some interesting observations. We started the bots back to back
as shown in the lego video, and our New Year video here:
http://homepages.ihug.co.nz/~rjtp/LegoSumo/RobotSumo.mov At Burnside High
they built sumo bots a year or two back and the bots had difficulty finding
each other when the target bot was at an angle providing little reflected
ultrasound signal back to the sensor. So we set Gnasher off at an angle to
the opposing bot. Gnasher immediately fell off the ring, and subsequently
did not find Topple at a 45 degree angle. So there might be some
improvement opportunities here. Improved search algorithms for finding bots
a awkward angles, stealth bots that are hard to find, and more sensors to
reduce incidence of topple.

Sue Linscot from http://www.robokits.co.nz/ brought along a tracked robot
kit and which she assembled during the evening with a lot of 'help' from
William and Scot. Sue decided not to enter the Sumo as the tracked bot did
look small and sophisticated next to the brutish Lego bots. Maybe we should
have a lightweight class just to keep things fair.

By 8pm battle was all done and it was bedtime for some of us. Sorry to
those who could not make it earlier and found us gone.

Our next session is on Wed 18th Feb 2009 at 6.30pm in the Science Alive
Seminar Room. Topics will be the Robo Sumo Challenge, anything else that
people choose to bring along and hopefully plenty of interesting items for
the free stuff table. See http://kiwibots.org for directions.

Richard Jones