Page 209 - Innovations in Intelligent Machines

202 S. Pr¨uter et al.
RoboCup soccer is of particular interest for many AI-researchers, because
it combines engineering tasks, such as building robot hardware and designing
electronic components, with computer science applications, such as localiza-
tion of objects, finding the robots’ positions, and calculating the best path
through obstacles. Another interesting challenge emerges from the require-
ment that all team members have to communicate with each other in order
to develop a cooperative behavior. Research on artificial intelligence may help
find the optimal solution in all of these areas. Within the field of RoboCup
soccer, the small-size league (SSL) allows for pursuing the research mentioned
above at a relatively low budget.
Fig. 1 illustrates the general setup used by all teams of the small-size
league. Two cameras are mounted approximately four meters above the floor
and observe a field of four by five meters in size on which two teams each con-
sisting of five robots play against each other. The cameras send their images
to a host PC on which an image processing software determines the ball’s
as well as robots’ positions. Depending on all recognized positions a software
component derives the next actions for its own team members such that the
team exhibits a cooperative behavior. By utilizing wireless DECT modules,
the PC software transmits the derived actions to the robots, which execute
them properly and eventually play the ball.
Fig. 2 shows the omnidirectional drive commonly used by most robots
of the small-size league. As can be seen, an omnidirectional drive consists of

control control
PC PC

team 1 team 2

Fig. 1. The physical setup in RoboCup’s small-size league

y F 2 F 2y
a
wheel 1 wheel 2

a a
a x
F F 1y

F 3
wheel 3
Fig. 2. An omnidirectional drive with its calculation model