BottleSumo Robotic Competition

Lego Mindstorms EV3 or NXT Invitational

(Game idea and rules adopted from Robofest 2017)


Game Objective and Synopsis

The objective of BottleSumo is for an autonomous robot to either be the first robot to find and intentionally* push a two-liter bottle (filled with 1 liter of water) off the table OR be the last robot remaining on the table. The bottle will be placed at a location that is the same distance away from each robot.  A robot is considered off the table when any part of it is touching the floor.

Summary of Rules

A robot is declared the winner of a game if one of the following criteria is met:

Each robot must be fully autonomous. No human control, signal, or remote computer control (tele-operation) is allowed.

(*) Intentionally pushing the bottle off the table is defined as “the robot pushes the bottle off the table with any side of the robot that has a sensor, while neither the robot nor the bottle is in contact with the second robot.” See the figure to the right. Robot A is not in contact with B or bottle.

Unintentionally pushing the bottle off the table is defined as “when the bottle falls off the table while both robots are in contact with each other [see (a) and (b) below], or when a robot pushes the bottle off the table with a side that does not have a sensor, as in the case when a robot is spinning [see (c) below], for example.”

As shown in figure (d) above, suppose B pushed the bottle off the table. It is an unintentional (not a clean) push, since the bottle was touched by robot A.

How to start the game?

A robot must wait 5 seconds after the game is started during which a judge will place a bottle on the table approximately equidistant from each robot.

Robot Requirements

Teams must bring a fully-constructed robot to the competition with a label clearly indicating their team number and the “front” of their robot. Teams will need to bring laptop computers to modify their programs to solve the unknown starting task as well as to adjust their programs for the lighting conditions, floor color, and table color, etc. that are unknown until the competition day. The following table shows details about robot specifications.

Maximum Robot Weight


Robot brick

Lego NXT or EV3

Maximum robot width, length, and height

Must fit in 25x25x25cm box. Robots may *NOT* expand their dimensions during the game.

Number of robot bricks(brains) per robot


Number of sensors

At least one sensor that can detect dark/light contrast on the same plane AND at least one sensor that can detect objects

Motor types


Number of motors

Maximum 3


Any. You may use tape, glue, rubber bands, etc. (However, you cannot glue/tape the robot to the sumo ring floor.) Vacuum or sticky tires are not allowed.

Programming language


Game Playing Field Table

The tables that are used for the competition is about 61 cm x 120 cm plastic folding table. The four corners of the table are rounded. The surface is light in color, for example, almond, tan, or gray. The table is placed on a dark colored floor with the legs folded under. The table can be raised up with rolls of packing tape for example, (we recommend a stack of three) as shown in the figure. The exact size, color, brightness, and edge shape are unknown until the day of the competition.

A two-liter bottle is covered with A4 size (21cm x 29.7 cm) white paper. Red electrical tape or color paper is used to create a red stripe as shown in the figure. The exact color of the red tape is unknown until the competition day.

Competition Procedures

  1. All the robots are impounded. During impound robot size and weight will be checked. Judges will also inspect the robot for any illegal materials.
  2. The bottle is placed at an unknown location equidistant from the two robots during. The bottle location can be different for each Game. (See the blue dashed line on Figures below).

  1. If the robot violates the starting requirements, the robot automatically loses the game, unless the other robot also violates the starting requirement, in which case it is a tie.
  2. At the start of each game, the judge will announce (a) the location of the robots on the table and (b) the orientation of the robots (For example, see Figure 1 and 5).
  3. Immediately after the Judge gives the signal to start the game, each robot must satisfy the starting requirements (5 second delay.) Students/judges must move at least 1 meter away from the table edges and may not approach the table until after the end of the game.
  4. If any piece/part of the robot falls off or is intentionally released from the robot, the robot is considered “off the table”. The other robot will be declared the winner if it remains on the table for 3 seconds.
  5. If the bottle is pushed off the table unintentionally (by chance), the game continues with head-to-head sumo wrestling.
  6. A maximum of 2 minutes is given for each game. A tie game will be declared if the judge determines that:
  1. Both robots at the same moment have any of their parts touch the floor.
  2. The robots both fall off the table within three seconds of each other.
  3. NO progress is being made for at around 20 seconds. The judge will announce a “Ten-second countdown” and begin a 10-9-8-7-6-5-4-3-2-1 countdown out loud before ending the game.
  4. BOTH robots fail to start.
  5. There is no winner after two minutes.

  1. If the match is a tie, then the tie breakers will be (1) the time trial result (2) additional game(s) up to 2 additional games (3) tie-breaker time trial with one bottle.