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Sumobot Tournament Rules

Sumobots are small robots that compete to push each other out of the ring.


ExampleClassMaximum SizeMax. HeightMax. Weight
Mini10cm x 10cmUnlimited500g
LEGO15cm x 15cmUnlimited1000g

Ring Size

Registration Rules

  1. A robot must fit within a square tube of the appropriate dimensions for the given class. A robot may expand in size after a match begins, but must not physically separate into pieces, and must remain a single centralized robot. Robots violating these restrictions shall lose the match. 
  2. The total mass of a robot at the start of a match must be under the designated weight for the given class.
  3. Robots must be autonomous. Any method of control may be used, as long as it is fully contained within the robot and receives no external signals or directions (human, machine, or otherwise). 
  4. Autonomous robot operation must begin automatically five seconds after being started by the user. If the robot starts before 5 seconds they forfeit that round's point. 
  5. Robots must move autonomously at least one full robot length.
  6. The robot must have a name or number. Display this name or number on your robot to allow spectators and officials to identify your robot.

Material Rules

  1. Jamming devices, such as IR LEDs intended to saturate the opponents IR sensors, are not allowed.
  2. Parts that could break or damage the ring are not allowed. Do not use parts that are intended to damage the opponent's robot or its operator. Normal pushes and bangs are not considered intent to damage.
  3. Devices that can store liquid, powder, gas or other substances for throwing at the opponent are not allowed.
  4. Any flaming devices are not allowed.
  5. Devices that throw things at your opponent are not allowed.
  6. Sticky substances to improve traction are not allowed. Tires and other components of the robot in contact with the ring must not be able to pick up and hold a standard 3"x5" index card for more than two seconds.
  7. Devices to increase down force, such as a vacuum pump or magnets, are not allowed.
  8. All edges, including but not limited to the front scoop, must not be sharp enough to scratch or damage the ring, other robots, or players. In general, edges with a radius of greater than 0.005", as would be obtained with an unsharpened 0.010" thick metal strip, should be ok. Judges or competition officials may require edges that they deem too sharp to be covered with a piece of tape.

Match Summary

  1. One match shall consist of 3 rounds, within a total time of 3 minutes, unless extended by the judges.
  2. The team who wins two rounds first, or receives 2 points first, within the time limit, shall win the match.
  3. When the match is not won by either team within the time limit, an extended match may be fought, during which the team who receives the first point shall win.


A point will be given when:

  1. A team legally forces the body of the opposing robot to touch the space outside the ring, which includes the side of the ring itself.
  2. The opposing robot has touched the space outside the ring on its own.

When a wheeled robot has fallen over on the ring or in similar conditions, points will not be counted and the match continues.

If the robots are entangled or orbiting each other with no perceivable progress for five seconds no progress is called and the robots are reset. No points will be counted.

A point will be taken away if a player:

  1. Utters insulting words to the opponent or to the judges or puts voice devices in a robot to utter insulting words or writes insulting words on the body of a robot, or performs any insulting action.
  2. Demands to stop the match without appropriate reasons.
  3. Takes more than 30 seconds before resuming the match, unless the judge announces a time extension.
  4. Starts operating the robot within five seconds after the chief judge announces the start of the match.
  5. Does or says something that alters the fairness of the match.

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