“What are the people doing on the computers back there?” We are often asked when we have spectators as we prepare for the game. Robot soccer is a difficult thing! 15 students are involved in the Bembelbots, who take care of various tasks, such as evaluating the camera images or playing strategy. Everything is different on the pitch! That is why small improvements are often worked on until the last second. If something doesn't work as planned, a solution is feverishly searched for. We start preparing the robots about half an hour before the game. New batteries are quickly inserted, the on-board computer receives the latest program, and the robots are marked with red or blue ribbons, depending on the team, so that you know who belongs to which team. Shortly before kick-off, the robots are switched on and then we can start…. The trainers on the computer now have to wait and watch, they are no longer allowed to intervene. Everyone is excited when the cute robots run across the field. Now success or failure of the work is evident. It's good when you can laugh at the mishaps of your own robots or really cheer about the first goal!

What is the RoboCup?

Robot soccer players compete in national and international RoboCup tournaments. There are different leagues in which robots of different types can compete. There are large, wheeled robots that play with a real soccer ball and very small robots that move on a tabletop. You can find leagues with self-built robots, and leagues in which all teams use the same robots. We play in the “Standard Platform League”, in which all teams use the two-legged robot “Nao”. The challenge for the teams is to teach the robot how to play soccer.
In Germany there are around 10 teams from different universities that compete in the Standard Platform League. We meet annually for the “RoboCup German Open” competition in Magdeburg, in which teams from Germany and Europe take part. The World Cup also takes place annually, this year in Istanbul. By the way, the world champion in the Standard Platform League is the “B-Human” team from Bremen.

Like a real soccer game ?

The playing field in the “Standard Platform League” is 6 × 4 meters. Both teams are on the field with up to four robots each, which have to decide what to do on their own during the game. And of course the game also has rules enforced by a team of four human referees. The most common foul is "pushing", i.e. bumping into other players, which is punished with a time penalty of 30 seconds. The halves each last 10 minutes, but the teams can take 5-minute breaks, for example to repair or replace defective robots.

The Nao Robot

Why do all robots look the same? This is the most frequently asked question on the sidelines. We play in the “Standard Platform League”, in which all teams use the “Nao” robot, which is manufactured by the French company Aldebaran Robotics. It weighs approx. 4 kg, has 23 joints and is therefore very flexible. Because the robots are supposed to play soccer independently, they have a small computer on board that they use to decide what to do. If you buy such a robot, it cannot yet play football. The teams first teach the little two-legged friend how to get up. After that, more complex movements are on the agenda. It is really complicated to teach the robot to see. The robot can see with a small camera in its head with which it looks at the playing field. So that the robots can find their way around the field, you have to look around and look for the colorful goals, for example. That is why the goals are painted yellow or blue and the ball is red. Sometimes we wonder why the robots are so blind and simply do not recognize the goal or the ball, even though it is not difficult for us humans. A robot is still having a hard time ...

Institute of Computer Science

Johann Wolfgang Goethe-Universität Frankfurt am Main
FB 12, Institut für Informatik
Robert-Mayer-Straße 11-15
D-60629 Frankfurt am Main