LuckStar II Diary
RoboCup 2001, Seattle
1 August. We arrived in Seattle after an arduous 17 hour flight, excluding a 3 hour stopover at Tokyo. The rest of the day was spent visiting the Public Market Place at Pike Street and taking photos with those handsome pigs all over the city.
2 August. Setup day 1. Everything went smoothly except for the camera. We had severe chromatic aberration with many blue and red color artefacts that were not supposed to be there. Any small-sized league robocupper would know that these extra red and blue pixels are a source of problem. But we were not too worried as we had brought along a spare camera until we realised that that we packed in the wrong lens for the spare camera. Back to our first choice camera.
3 August. Setup day 2. The day was spent busy training the vision system, adjusting and callibrating the camera. We also enhanced the ball tracking code to take care of the extra red pixels and ball occlusion by tall opponent robots. Nothing else much happened.
4 August. Preliminary round day 1. Our first opponent was HWH-Cats from Taiwan. They were not really ready to compete and were there for exposure and learning. After scoring 4 goals, they decided to forfeit the game. Next, we played against the local vision team, Omni, from Japan. With our global vision advantage, we had no problem beating them 10-0. By now, we realised that our main opponent in this group was 5DPO from Portugal. We had to beat them in order to avoid meeting BigRed from Cornell University in the quarter-final, our toughest and most formidable opponent, who had denied us of a place in the finals for the past two consecutive years.
5 August. Preliminary round day 2. Huskies, our next opponent, did not show up. We had a fairly relaxing day. Most of our time were spent assessing our would-be opponents and devising strategies against them. We focused on Roboroos, FU-Fighters and BigRed.
Roboroos from Australia had robots that shoot the ball like a bullet. That gave them a huge advantage in free kick situation so we had to make sure that our goal mouth would be well-covered from most angles.
Fu-Fighters from Germany was fast with both wheel-chair based robots and omni-direction robots. It's hard to predict how they will play their game and I guessed our best defense is to let our robots run at maximum speed.
BigRed played a very controlled game and had beautiful passes. Their favourite trick was to bring the ball to one corner of the field and passed the ball to another player at the other corner. It would be difficult to block the pass as only the goalie was allowed into the defense area. Their only problem seemed to be that the pass must be very accurate in order to be successful. The player receiving the pass did not seem able to adapt to inaccurate pass. My guess was that if the goalie and defender were well placed such that there would only be a narrow path for the ball to passed through, that would reduced their passing effectiveness.
6 August. Preliminary round day 3. As expected, the game against the 5DPO was the toughest. We ran our robots at full speed and that must have caught them by suprise. In the previous 2 matches, we ran at about 60 percent full speed. The match was pretty close but we still managed to score 5 goals against them.
7 August. Intermission day 1. We spent the best part of the day enjoying Seattle. The night was spent setting up the system as we were going to play in another field. We also discussed and try to finalise the tactics to be employed against BigRed.
8 August. Intermission day 2. We spent most of the time trying to devise a simple effective way to block BigRed passes from the field corners. That night, we worked till 4.30 am coding and testing our improved defense strategies.
9 August. Quarter and Semi-finals
Morning. Quarter-finals. The first match was BigRed against 5DPO. It was a suprisingly close match. 5DPO had improved on their speed and had a defense strategy against BigRed that was exactly just like what we had devised. The defense strategy seemed to work quite effectively. Still, BigRed managed to beat 5DPO by a 2-1 score.
In the second match, FU-Fighters beat Rogi from Spain. Rogi had performed well but their robots did not have kicking device, a huge disadvantage in this competition.
In the third match, underdog ,SP Rangers beat one of the top contenders for last 4,Roboroos, by 1-0 during extra time.
Our quarter-final match was against KU-Boxes from Japan. As this team robots lacked kicking device, we were not threatened by them. We managed to score 10 goals against them.
Afternoon. Semi-finals. The unthinkable happened. Pre-tournament favourite, BigRed, was beaten 1-0 by SP Rangers in a game which saw little action. We just realised that all our previous day efforts and sleep sacrifices had gone down the drain.
Our game against FU-Fighters was the most exciting so far. Both teams were almost evenly matched speed-wise. FU-Fighters robots were more rugged. They were always winning the side balls and able to push close to our defense. Fortunately, their attacking robots had the knack for kicking the ball off-field, thus giving us lots of free kicks. Those free kicks helped us to clear the ball to the opponent's defense area. In the end, we managed to score 4 goals against FU-Fighters, mostly from free kicks conceded to us. When the final whistle was blown, we all heaved a sigh of relief. We were in the final.
Night. After the Robocup dinner, we were back at the field trying to see if we could improve on our game for the final against SP Rangers. The SP team had a strong and fast defense but a relatively slow attack. Our main worry was ball occlusion as their robots were pretty tall. We spent a bit of time testing the ball-tracking code. By 1:30 am, we were very sleepy as we hardly slept the previous night. We decided to rest. Still we managed to have a good game of frisbee in the quiet exhibition hall. We slept at 2:30 am.
10 August. Final.
The morning started off with the 3rd-4th placing match between FU-Fighters and BigRed. It's was most eventful, entertaining, and filled with lots of goals. In the end, BigRed triumphed with a 6-5 scores.
Next was our final with SP Rangers. The game was fairly slow with lots of jostling for the side balls. We managed to keep the ball in the opponent side of the field most the the time. When the game ended, we netted 3 goals, not too bad, considering that they beat BigRed and Roboroos. If the final game had been more exciting, it would make the victory sweeter. But still, a win is a win, and we were champion of the 2001 RoboCup small-size league.
Post-mortem.1) Our robots lacked the means to clear ball from the walls in a controlled manner, which meant that there were lots of opportunities that we could not capitalise upon. We will make sure that our new robots have those dribbling devices.
2) From Cornell's games, we noticed that passing was only effective against slow moving opponents. I believe that the field has to be significantly enlarged (both width and length) in order to have effective passing.
3) Both the finalist teams used wheel-chair based robots, whereas the trend seems to be towards omni-directional drive robots. From the result, I think there is still future for wheel-chair based robots.
4) Our robot handler, Wai Yee, was so excited and nervous that he lost his ability to communicate. When asked to move the right field robot up, he moved the left field robot down. That had caused a little bit of unnecessary frustration. It is important to select someone with the right temperament to handle the robot. Nevertheless, he had done a good job.