Wikipedia
Robot-sumo, or pepe-sumo, is a sport in which two robots attempt to push each other out of a circle (in a similar fashion to the sport of sumo). The robots used in this competition are called sumobots.
The engineering challenges are for the robot to find its opponent (usually accomplished with infrared or ultra-sonic sensors) and to push it out of the flat arena. A robot should also avoid leaving the arena, usually by means of a sensor that detects the edge.
The most common "weapon" used in a sumobot competition is an angled blade at the front of the robot, usually tilted at about a 45-degree angle towards the back of the robot. This blade has an adjustable height for different tactics.
Robot-sumo is divided into classes, fought on progressively smaller arenas:
- Heavy-weight. Standard in the National Robotics Challenge. Robots may weigh up to 125 pounds and fit in a 2-foot cube.
- Light-weight. Also standard in the National Robotics Challenge. Robots may weigh up to 50 pounds and fit in a 2-foot cube.
- Standard class (sometimes named Mega-sumo) robots may mass up to 3 kg and fit inside a 20 cm by 20 cm box, any height.
- Mini-sumo. Up to 500 g mass, 10 cm by 10 cm, any height.
- Micro-sumo. Up to 100 g mass, must fit in a 5 cm cube.
- Nano-sumo. Must fit in a 2.5 cm cube.
- Femto-sumo. Must fit inside a 1 cm cube.
There is also Lego Mindstorms NXT sumo robots, in which NXT robots compete. The robots usually have to fit in a one-foot cube.
Classes are further divided into remote-controlled and autonomous robots. Also, there might be a tethered category (varies)
Sumo robots are built from scratch, from kits or from Lego components, particularly the Lego Mindstorms sets. Some sumo bots are built with only wood and motors for more of a challenge. The usual size for the wood is 12" by 12". It makes it hard to construct a really large robot with this piece of wood.