While the first RoboCup was held in 1997 (Already before this a pre-RoboCup was held in 1996 in Osaka in conjunction with IROS 1996 Osaka.), the Humanoid League (HL) has no sooner been established than
2002 at RoboCup in Fukuoka. The reason for this rather late start in comparison to other RoboCup soccer leagues is due to the fact that biped walking was and partly still is a challenge in robotics. In the first years (2002-2004) the robots participating in the HL were quite diverse in many respects and had to be sorted into three sub-leagues in order to cope with the variety of heights ranging from 10 cm to over 2.2 m. The competitions consisted of walking challenges, a free style competition, and a penalty kick competition for all size classes. At that time external processing - even remote control - was allowed. In order to make results of the competitions comparable between the very different robots, performance factors had been introduced. These performance factors had to be applied to commercial platforms, remote control and external processing.
The Best Humanoid Award of the year 2003 went to the then participating HITS Dream Team who used the Honda Asimo robot for their performance.
Since the Honda Asimo robot had no opponent in the penalty competition of his size class the robot played against a child. The photograph of this incident still is shown on the RoboCup homepage.
Starting from earlier experiences many changes had been introduced into the competition making the technical constraints more specific than the in the previous rules. Performance factors were abandoned, and external processing as well as remote control were banned from the competition. Thus, processing of sensory information, behavior processing, etc. has to be completely self-contained within the platform. A maximum ratio between foot size and height of the center of mass had been introduced in order to encourage dynamic walking. The number of size classes was reduced from 3 to 2, of which the smaller class was called Kidsize class (smaller than 60cm) and the bigger TeenSize class. The total number of competitions remained the same, however, the free style competition was replaced by the regular 2 on 2 games in the KidSize class. In 2005 a total of 20 teams from 9 nations and regions participated. This was about twice the number of the year 2004. For the first time a qualification process had to be introduced.
Several teams had some background from other leagues and took the advantage to customize their software rather successfully for the new league.
The RoboCup 2005 was the first RoboCup where the Humanoid League was perceived as the most attractive of the RoboCup soccer leagues if not the most attractive competition of the RoboCup competition. In the TeenSize class the conductance of 1-1 games was discussed, but could not be carried out. One aim of the technical committee was and still is to lead the development towards current research problems. Dynamic walking and stability have been the most important issues then and still are up to now, which have been enforced by the technical challenges between the years 2005 and 2006. In the years 2005 and 2006, a rough terrain challenge has been conducted in which the robots have to cross a field of hexagonal tiles of random height. The technical challenges change every year. The rules have been further refined for the competitions in 2006 (Bremen) and 2007 (Atlanta) in many aspects, in particular with respect to the conductance of the 2 on 2 games. Also the footrace competition was introduced to the TeenSize class in order to have an equal number of competitions in the Teen- and KidSize classes.
The rules of 2005 and 2006, and the example of relatively cheap and powerful robots gave a new perspective to many interested people in the RoboCup community and also people from outside who were interested in setting up a team. Team Osaka received the Best Humanoid Award again, as well as in 2006, 2007 and 2008. At RoboCup 2007 in Atlanta a total of 29 teams participated, of which 22 were from the KidSize class and 7 from the TeenSize class. The technical level of the participating teams increased significantly. Although the finals of the 2 on 2 games in the KidSize class were won by Team NimbRo for the first time, due to a better performance in the Technical Challenge Team Osaka was able to win the Best Humanoid award once again.
Norbert Michael Mayer