Lego Robot Sumo

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About Robot Sumo

Sumo is a very popular sport in Japan and is known around the world. Two really big guys get up on an elevated platform, the Sumo ring. The goal is to push the other guy out of the ring or throw him to the floor. It's basically king of the hill. The national Sumo competition is held in Japan the middle of each odd numbered month (January, March, etc.).

Robot Sumo started in Japan and is now the most popular robot competition worldwide. We use the simplified rules below, which are based on the official Japanese rules.

For some great pictures of Lego Sumo robots that will give you good ideas on building your own robot, visit the web site of the Central Illinois Robotics Club. Look at the Lightweight class and Lego class robots.

Objective

Push the other robot out of the Sumo ring two times in a three minute period.

Playing Field

The Sumo ring is 30 inches in diameter and made of black painted plywood. There is a 2 inch wide white border. Two thin starting lines mark the no-mans zone in the middle. Robots must start behind these lines.

Robot Construction

• Maximum size 8 inches long x 8 inches wide. No height limitation.

• Maximum weight 2.2 pounds

• Parts are limited to any official or compatible Lego piece, rubber bands, removable tape, and cardboard. Not allowed: glue, anything that damages the Lego parts, vacuum or sticky wheels.

• A maximum of 3 motors may be used.

Match Rules

• A match consists of up to three games.

• The first robot to win two games wins the match.

Game Rules

• To start a game, players position their robots anywhere behind the starting line on their side of the ring.

• When given the signal, both players press their start buttons simultaneously then move back out of the way so spectators can see.

• Players cannot touch their robots or enter the ring for the remainder of the game.

• The robot must start moving 5 seconds after the start button is pushed. If a robot does not wait 5 seconds it is disqualified.

• A robot wins a game when it pushes its opponent out of the ring or if the opponent moves out of the ring by itself. The opponent's robot must touch the floor outside the ring.

• If any of the following occur the game will be restarted:
  1. Both robots are locked together and stop movements for 30 seconds, or are stuck in the a repetitive pattern for 30 seconds. 
  2. Both robots move or stop for 30 seconds without touching each other.
  3. Both robots at the same moment touch the space outside the Ring.
     

• If one robot stops it's movement for 30 seconds, he shall be considered not having the will to fight, and the opponent shall win the game.

• If neither robot moves outside the ring within 2 minutes, the judge will decide the winner based on technical merit of the movements and operation of the robots and attitude of the players during the game.

• Your robot may not send IR messages to the other robot.

Deciding the Winner

The winner will be decided by a double elimination tournament.

Hints and Tips

This contest requires a light sensor. See Lego robot examples and tutorials for ideas on how to solve this problem.

Might it be possible to sense the other robot with a touch sensor, then flip it over with a robot arm powered by a third motor? That would really be Sumo!