People have some odd hobbies, such as collecting Planet of the Apes figurines, competing in the international air guitar championships and building jet engines from garage parts, but robot soccer?
This competition has developed to the point where there is now a long history of international competitions and, unlike people soccer where Australia was knocked out of the World Cup in Brazil last year without winning a game, in RoboCup soccer, we rule. A team from the University of NSW won the RoboCup SPL World Championships in China for the second time in a row in late July, beating off a strong German team 2-1.
The small - about half a metre high - humanoid RoboCup players are produced by French company Aldebaran Robotics and used by all the teams in the five-a-side competition played on an indoor field to match the size of the competitors. The robots have two inbuilt cameras, about the same processing capacity as a high-end mobile phone, and can communicate with one another but, crucially, cannot take human coaching while on the field. The five robots are on their own, in taking on the opposing five robots.
In the early days of RoboCup soccer, as Australian team leader Sean Harris agrees, there were odd results, with robots standing still while others kicked the ball around in front of them. But now the robots, which were changed to the now-standard humanoid figures in 2010, are behaving much more purposefully, albeit with limitations.
As Harris, a PhD student in robotics and artificial intelligence at the University of NSW, notes, one of the difficulties is vision. The robot players have to recognise the ball without any of the high-end processing systems that permit commercial robots to "recognise" objects.
The software devised by his team is broken up into modules, with one module taking a rough and ready but still effective approach to recognising the ball, while another handles walking (also difficult for a robot), another works out where the robot is on the field, another deals with playing strategy and so on.
These Roboroos - the official name is just University of NSW, but they wear yellow jerseys - move much faster than the other robots in the competition, a whole 30 centimetres a second (1km/h), because their software has a better balancing algorithm to stop the robots falling over. So the team's basic strategy depends on that speed. Harris says that if the ball is in their half, the Aussie robots don't bother with passing. They kick the ball hard and hope to run it down before the other team can get there.
In the nail-biting decider, the German team had a very defensive strategy which, Harris says, at one point resulted in all five German robots standing in front of the goal.
The University of NSW group cannot afford another five robots to hold practice matches, but they have practices to test what effect the latest set of changes in the regularly revised software has on their players, as well as holding three-on-three matches to test strategies.
An additional complication with this year's competition in China was that of a starting whistle. Referees blow their whistle and human players start a game, but getting robot players to reliably hear the whistle is surprisingly hard. The Roboroos have a voting system. If a majority of players decide that they have heard the starting whistle then they start playing.
There is also more to RoboCup than just soccer.
There is a RoboCup Rescue, where teams of robots have to enter a model disaster site, littered with debris and even moving parts, work out which of the many items they can see are victims and which are not - again, tough for robots - and co-operate to bring those victims to safety.
There are those who, oddly, disapprove of such activities. They worry about the corrosive effect such a pastime will have on the moral fibre of humans who play sport, and that the use of robots will cause mass unemployment. These complaints, equally oddly, be can be mixed in with diatribes about automated answering systems, which never direct callers to a human being.
The reality is that skills and techniques learnt getting a robot figure to kick a goal, or defend one as a robotic goalkeeper, can be used to make the already widely used industrial robots more productive, or expand the roles in which they can be used, in a process that has been going on since the industrial revolution.