The Bremen B-Human team took second place in the Standard Platform League at the RoboCup 2015 world championships held recently in Hefei, China,. Three out of the six trophies awarded during the event went to Bremen. Along with second places in the soccer and select-team matches, they took first place in the technical category. The Bremen B-Human team is a joint project of the University of Bremen and the German Research Center for Artificial Intelligence. This year the world Championship title was again won by the University of New South Wales (UNSW), Sydney, Australia.
The final match against the reigning world champions UNSW was a repeat of last year‘s semi-final. This time, though, the score 1:3 was not such a walkover as in 2014 – although for the four-time world champion B-Human team from Bremen it was still a bitter defeat. In the first half of play, UNSW Australia constantly attacked their opponents’ goal – only to be rebuffed by the Bremen defense. Just before half-time, though, they went into the lead. The second half was initially more balanced, with the ball changing sides frequently between the two teams. After six and a half minutes – a full half-time being ten minutes – the Bremen robots drew level and the score was 1:1. The Australian team then took time out, i.e. play was interrupted for five minutes. After the game recommenced and one minute before end of play they once again went into the lead with the score now 2:1. But this wasn’t enough for the robots from Down Under. Just six seconds before the final whistle they scored their third goal of the match with a long shot which the Bremen goalkeeper could only stop after it had crossed the line. All in all, it proved to be a truly exciting final.
The select-team match
Beside the “normal” soccer tournament, on the past two occasions the RoboCup has also included a select-team match. This involves mixed squads of NAO robots playing in changing composition. Each participating team fields a player that has to cooperate with robots from other teams. Although the object of the exercise is still to win, the main focus is on how well this robot is able to abide by the rules and coordinate play with other members of the team. This is evaluated by a panel of judges on a points basis. Last year B-Human was the winner in this category, and at this year’s event they came out tops, too. Nevertheless, although the HTWK Nao Team was a few points behind in this particular category, they were more successful in other matches and managed to push B-Human into second place. In the overall event the four first places went to teams from Germany, namely Leipzig and Bremen, followed by the Nao Devils from Dortmund and Berlin United.
Traditionally, the RoboCup also encompasses competitions in the technical category. These entail the robots having to solve tasks which may have an effect on how the championships will be run in future. One of this year’s tasks was the corner kick, for which up to now there have been no rules. In a lead-up to one day being able to play on a real turf, a second challenge comprised walking on different carpeted surfaces. And a third task involved playing with assorted balls: up to now only one type of brightly colored ball had been in play. B-Human came second out of a total of 27 teams in all three technical challenges and was consequently declared overall victor in the technical contests.
Currently, the B-Human team comprises 10 students of the University of Bremen and their supervisors, Dr. Thomas Röfer from the DFKI Research Group Cyber-Physical Systems, led by Professor Rolf Drechsler, and Dr. Tim Laue from the University of Bremen. B-Human has been participating in the Standard Platform League of the RoboCup German Open and the World Championship since 2009. In that time they have been German champions no less than seven times – and four times world champions.
All teams in the Standard Platform League use the same NAO robot model developed by the French firm Aldebaran Robotics. The difference between the teams lies in the software used to drive the kickers. Thanks to clever software, the NAOs are able to move around completely autonomously. During matches they have to be able to recognize details of their surroundings, arrive at subsequent decisions, and then implement the results in a team effort. The soccer matches entail teams of five robots competing against each other.
Three major changes were made to this year’s world championship: The goal posts are now white instead of yellow. This makes them more difficult for the robots to discern as white is a much more common color in the ‘pitch’ surroundings, and because the NAOs are white themselves. In addition to this, teams are now permitted to design and wear their own shirts, making it easier for spectators to identify which teams are playing. This, in turn, creates a greater challenge for the robots to distinguish between team members and their opponents. This year‘s third new challenge is that the NAOs competing in the semi-finals and the final match have to be able to identify the referee’s whistle commands. In order to master this challenge, the B-Human robots have been trained to identify a particular whistle tone so they don’t react to the whistling going on around them in a hall full of other football pitches. Unfortunately, some of the whistles used in the championship matches produced different tones, and this confused the B-Human squad. Other teams were equipped with a greater tolerance for distinguishing between tones. Although this facilitated identification, the robots sometimes perceived to have heard the referee‘s whistle when it hadn’t actually been blown.
About the RoboCup
The RoboCup is an international initiative to promote research in the areas of artificial intelligence and robotics. The commonly shared goal is by the year 2050 to develop a team of autonomous humanoid robots that will be able to play successfully against the then reigning human world champions. In order to attain this ambitious goal the championships are divided into different leagues, each with their own specific research foci. Every year the teams have to meet increasingly complex requirements.
If you would like to have more information on this story, please contact:
University of Bremen
German Research Center for Artificial Intelligence (DFKI) GmbH
Research Area Cyber-Physical Systems
Dr. Thomas Röfer
Phone: +49 421 218 64200
e-mail: Thomas.Roeferprotect me ?!dfkiprotect me ?!.de