MiRobotClub holds a Sumobot competition, once in a while.
The rules we used were derived from the 24tooth rules for Sumobot6 (missing, but I believe they were missing at the time.) The Sumobot6 rules were derived from the Sumobot5 rules with some simplifications. I'll cut and paste from the Sumobot5 rules, which are still available on the Wayback machine. :
In our competition, we had a mostly pure Lego class, and an any technology class. The mostly pure Lego class required that all of the motors, mechanisms, and structural elements had to be genuine unmodified Lego, but the electronics could be any technology.
Control: All robots are to act autonomously, that is to say, robots must operate without human control during a match.
Weight: The total weight limit for a robot is 2 pounds. All robots will be subject to a weigh-in process at the beginning of the event to determine their weight.
Size: At the start of a match the robot must fit into a square box of 12 inches to a side, with no height limitation. Parts of the robot may extend outside this region after a match has started.
[Original class section was here, but see above. -paulh]
[Modules were dropped for Sumobot6. They were too complicated. -paulh]
Sumo Ring Details: The sumo ring has a diameter of 4 feet, and is raised about 4 inches above the floor. The color of the ring is Krylon Ultra Flat Black spray paint, with a 2 inch wide Krylon Flat White spray paint edge boundary. The surface of the ring is smooth due to it being made from "finished plywood".
Prohibited Items and Actions: A robot may not spray any material on the ring or on their opponent, or in any way deform the sumo ring. Robots are not allowed to use any flying components or projectiles. Robots may not electromagnetically interfere with the other robot or its sensors. Overt attempts to damage the opponent's robot, over and above the expected ramming and pushing, are not allowed. No rotating blades or flame-throwers!
Allowed Items and Actions: A robot may use various forms of detection to locate the other robot (IR, sonar, touch...). It may also incorporate stealth technology to avoid detection by the other robot. Providing an environment which misleads the opponent's robot is allowed (for example, putting a black flap down over the white ring edge line, hoping the other robot will not detect the edge and fall off). Signals may be used to try to confuse the other robot's detectors, such as flooding the area with IR, touching the far side of the robot, or convincing the other robot it is at the edge of the ring.
[Ignore the stuff about the RCX. There are no restrictions on what or how the computer on the robot does its thinking, as long as it is contained within the robot. -paulh]
Match Rules: Each match (the full contest between two robots) has a limit of three minutes or three bouts (each battle between two robots), which ever comes first.
Bout Start: The robots are placed on the sumo ring at the
designated starting positions. Starting positions is defined as side-by-side in center of ring, spaced 6 inches from each other and facing in opposite directions. There will be a starting block that will indicate which direction the robots should face and will also maintain specified spacing. The direction a robot is facing is defined by it's initial, perceptible, direction of movement. A referee signals the start of each bout. The builders will indicate to their robots the start of the bout. Each robot should have a 5 second delay after the builder pushes run before the robot starts to move.
Bout End: A bout ends when...
* ...the first robot touches the area outside the ring. * ...the robots are deadlocked for 30 seconds. * ...both builders agree on a draw. * ...the match time expires.
Bout Scoring: At the end of each bout, both robots are awarded
points as follows:
* 2 points for a win * 1 point for a draw * 0 points for a loss
Match End: The match is over when either 3 minutes has elapsed or
3 bouts have concluded.
Match Scoring: After the match, the robot with the most bout
points receives 1 match win. If the robots have the same amount of bout points, each receives .5 match wins.
Event Scoring: At the end of the day, the robot with the most
wins, is the champion. If there is a tie, the robot with the most points is the champion.
Repairs and Reprogramming: During a match no changes in programming or construction of the robot is allowed, though minor repairs or battery replacements are allowed. There will be a maximum of one minute between bouts for these repairs. Reprogramming is allowed when the robot is on the sidelines (not actively in a bout or match).