02-19

Computer Vision and Control for Soccer Robots - The FU Fighters Team

We have built two teams of soccer playing robots at the Free University of Berlin that have taken part in several RoboCup tournaments, the yearly robotic soccer world championship. In the small-size league, five autonomous robots play against other five using the image provide by a video camera hanging from the ceiling. In the mid-size league, four robots play against four using their own video camera and carrying a laptop. In this league the field measures 10 by 5 meters. In this talk, I will explain the computer vision techniques we have developed for dealing with varying lightning conditions in an extremely dynamic environment. Image segmentation and classification must be done in real time, at 30 or more frames per second. I will also explain the hierarchical control architecture we developed. Control is done using physical and virtual sensors that activate reactive behaviors with different temporal characteristics. The behaviors activate real or virtual actuators that determine the robots movements. The small robots are extremely fast and controlling them in the appropriate way is a challenging problem. Recently we have been studying how to make the robots learn from their own experience on the field. We started by letting the mid-size robots calibrate their cameras and color segmentation tables automatically, without human intervention. In the case of the small robots we are investigating the use of reinforcement learning techniques for letting them optimize their movements and reactions. The FU Fighters have won three times second place at the RoboCup tournament (1999, 2000, and 2002), and have won the European Championship twice (2000, and 2002). I will show video footage of the last RoboCup competitition. For more information visit www.fu-fighters.de