Free University of Berlin Institute of Computer Science AI Group

F-180 Team

FU-Fighters

Motivation to participate in RoboCup SmallSize (F180)  Robotic soccer is fun  New benchmark problem for AI research  Interdisciplinary research  Focus both on individual robots and the team  SmallSize league needs only limited resources

Competitions  RoboCup’99 in Stockholm  first real games  second place  European competition in Paderborn  live broadcast on German TV (WDR)  inter league games (SmallSize & Mirosot)  winner  Show games ( Science Festival Bonn, Berlinale, CeBit)

Research issues  mechanical  fast, reliable robots  kicking devices  electrical  power supply  local control  second place  computer vision  real time object localisation and tracking  cope with occlusions, changes of lighting,...  behaviour control  individual actions  obstacle avoidance  ball handling  team play  communication

Mechanics and electronics  Aluminum frame to protect the electronics  Two individual DC-motors for differential drive  Passive sphere for third point of support  Shooting plate controlled by a third motor  On-board microcontroller Motorola HC05 Vision system  NTSC video camera (640x480 Pixel, 30fps)  Searches and tracks colored objects  Determines position of the ball, as well as position and orientation of all robots  Predicts positions in the next frame and investigates only small windows of the image

Behavior control  Reactive, layered system of sensors, behaviors, actuators within a time hierarchy  Higher sensory levels aggregate information  Higher-level behaviors modulate/configure lower-level behaviors  there is no explicit world model  fast reactions (reflexes) are possible

Behaviours  Level 1: drive to position, avoid obstacles  Level 2: approach ball, kick, dribble, free the ball,...  Level 3: decide which robot should take initiative  Level 4: passing,... (to be implemented)  Level 5: strategy changes,... (to be implemented)  Goal keeping behaviours Radio link  Transceiver working at MHz  9600/19200 baud  Error tolerant transmission  Packets contain target speeds for the motors  Local control of motor speed

Who built them ? Our Stockholm‘99 team was composed of three researchers and seven students. Some students left the team, but we have also new members. Upper row: Wolf Lindstrot, Prof. Dr. Raúl Rojas, Manuel de Melo, Dipl.-Inf. Sven Behnke, Oliver Tenchio. Lower row: Martin Sprengel, Dipl.-Inf. Bernhard Frötschl, Mark Simon, Peter Ackers, Andreas Schebesch. New team members: Lars Knipping, Jong-Gill Park, Jörg Solger, André Vratislavsky, Lars Wolter, Andrea Schuhmann, Kirill Koulechov Building a team of robots is time consuming, but rewarding. One does not only learn about robotics, but also about teamwork and deadlines.

Logistics  curriculum  started in spring ‘98  seminars  practical lab work  lab  permanent field  camera, computer, tools  access to university workshop  competitions  10 persons and 6 robots went to Stockholm by car  need a truck to move the field  funding  no solid funding yet  support from the university  show game  sponsors (parts and some financial support)

Publications RoboCup'99 (F180) Team Description: FU-Fighters, Team Descriptions RoboCup'99 Stockholm, pp , Using hierarchical dynamical systems to control reactive behavior, Proceedings IJCAI'99 - International Joint Conference on Artificial Intelligence, The Third International Workshop on RoboCup, Stockholm, pp , The Soul of a New Machine: The Soccer Robot Team of the FU Berlin, Technical Report B-12/99, Department of Mathematics and Computer Science, FU Berlin, 1999

Contact Prof. Dr. Raúl Rojas, Sven Behnke, Bernhard Frötschl {rojas, behnke, Internet: Phone.: / 131 / 133 / 100, Fax: / 109 Mail: FU Berlin, Institut für Informatik, Takustr. 9, Berlin, Germany Sponsors We thank Conrad Electronic, Faulhaber Motors, Siemens ElectroCom Postautomation and Lufthansa Systems Berlin for their material and financial support

Future plan: Omnidirectional local vision