Judo

The rules are relatively simple — the goal is to force the oponent robot down on the Tatami. Note, that what exactly means “robot on the floor” was not yet specified (the rules description is still in progress) . Robot can lose the match also in different ways — if it leaves the carpet or if it does not move for 30 seconds. Finally if within five minutes there is no winner the match is terminated and declared as a draw.

The contest is online and it is possible to watch matches every working day at www.cyberbotics.com/contest. The absolute winner will be known on the April 21st 2004 — the controller at the first place will get a Hemission robot sponsored by K-Team.

The first impressions were mixed — as well as the game rules the Webots simulator is still in the preparation phase. It is not very exciting to spend "a while" on the slow modem line to download the 11MB long program only to find out that it already out of date and that it is necessary to download newer version. Version 4.0.8 moreover does not contain any sensors for the humanoid robots, which is quite limiting. Finally it takes couple iterations before human being, or better the programmer, gets used to programming controllers in Java.

If you overcome initial problems then it is not that bad . I have to admit that I had a lot of fun with the 21 degrees of freedom of the robot. I got tired of changing few numbers and recompiling Java program again and again, so I wrote a very simple method for loading robot poses from a file. I was changing the file content while the controller was running, which is btw not very good idea, but in the worst case you could fix possible conflicts by reloading the whole world.

We decided, similarly as in the previous contest ALife3, make the code available. The first version, which will nail down the oponent robot with somersalut-roll, is available here: Judoka0.java. The program requires file of positions seq.txt.

Well, it is not very sophisticated and it is not even clear if it will run on the judo-server, but… better than nothing. We will see within a few days.