Newsgroups: comp.robotics
Path: brunix!sgiblab!swrinde!elroy.jpl.nasa.gov!ames!koriel!sh.wide!wnoc-tyo-news!nkkgw!damned!hattori
From: hattori@csrd.nkk.co.jp (Mato Hattori)
Subject: Re: Robot Sumo Contest Announcement
In-Reply-To: bsmall@iat.holonet.net's message of Tue, 23 Nov 1993 19:00:26 GMT
Message-ID: <HATTORI.93Nov24152844@gaea.csrd.nkk.co.jp>
Sender: news@nkk.co.jp
Organization: NKK corp.,Tokyo,Japan
References: <rowleyCGnHr5.1HH@netcom.com> <CGyKss.1s5@iat.holonet.net>
Date: Wed, 24 Nov 1993 06:28:44 GMT
Lines: 74

In article <CGyKss.1s5@iat.holonet.net> bsmall@iat.holonet.net (Brad Smallridge) writes:

>   I have attached the original message to this in case it should get
>   separated. My question is about strategy. The idea I'm thinking about are
>   arms that swing down from the main body of the robot at about an angle of
>   120 degrees, 60 degrees on both side of center. Now what I want to happen
>   is that the opponent gets trapped between these arms. If the opponent
>   swerves to the side on a flanking manuever, it would push against an arm
>   and swivel my robot around so that my robot is still pushing square on.
>
>   I believe that the arms are legitimate if they deploy from the 20cm square
>   area after the contest begins. Since there is no height limitation, I
>   imagine the arms pivoting down with gravity as soon as the contest starts.
>
>   My questions are: 
>   Is this a workable approach? 
>
>   Does anyone have any
>   experience using this technique?
>
>   If the arms touch outside the Duomo, 
>   has the robot lost?
>
>   What is the best wheel material 
>   for maximum friction?
>
>
   ...<reference omitted>...


I would like to answer your question as a participant of the original
Japanese Robot Sumo Contest.

I appreciate you idea of trapping arms.  The answers for your question
are as follows ;

1. Yes, it's already well known in Japan.

2. No, I personally don't have tried the idea.  Though, with my
   observation, it will work fine if you could make it enough durable.
   Try to trim the length of the arms.  It would not be effective if
   it's too short, and not good if it's too long.  Actually, the robot
   which had strong motors and 2 trapping arms, but no sensors, ranked
   in the best 4 last year.  I was surprised that it didn't have even
   white line sensors.  It had just rushed straight forward.

3. Yes, in the original Japanese rule, robot will lose when any part
   of body touches outside the Dohyo (the ring).  The only exception
   is small parts, which can be contained in 1 cubic cm, dropped from
   the body.

4. It depends on surface of the ring.  In my experiments, some sort of
   soft spongy rubber has good traction.  Try merchandised RC cars'
   wheels, and try to use some chemicals on them.  I can even provide
   a hint.  There is a color dot on RC cars' wheels.  "Black-Dot" is
   the best.  If you wish to have extremely strong friction, try to
   find carpet cleaner which has water washable very sticky jerry.


One more thing for all people going to try to build robot sumo
wrestlers, take care of speed of your robot.  Of course, the faster is
the better.  But, the faster you move, getting much difficult to stop.
I saw many robots stepped out of the ring by themselves, seemed to be
blind for the white line at the edge of the ring.  Even the white line
sensor works well, things with a certain mass cannot stop suddenly.  I
guess, at least, interrupt method, not polling method, is necessary to
handle the white line sensors.

Good luck for all!
--
Mato  Hattori                      Computer System Research Department,
email : hattori@csrd.nkk.co.jp     Electronics Research Center, NKK Corporation
voice : 81+44-322-6483 (office)    1-1 Minamiwatarida Kawasaki-ku
      : 81+44-246-9665 (home)      Kawasaki-city, 210 JAPAN
