Servo - September 2007

TUESDAY (Day 4)

GAME 1

Today marked our very first game! We went up against Team TKU from TanKang University, a RoboCup veteran since 2000. The situation for DARwIn didn’t look too good because we had been struggling to fix the problem of DARwIn 2B’s PC/104 computer all night, but could not find why it was not communicating with the rate gyros and motors through its serial port. After much discussion, we decided to swap the computers between

DARwIn 2B and DARwIn 2A, thus having the nonfunctioning DARwIn 2A as the goal keeper (essentially making it a “brick” in front of the goal), hoping that it would simply block the shots from our opponents by just sitting there. After a long and difficult “surgery,” we finally made DARwIn 2B, functional again. Due to the difference in texture of the playing field carpet, we were not able to use our analytically generated, awesome gaits, but rather manually recorded some hand-tweaked gaits on the spot so that it could at least walk on the field and play the game. The new walking gait was not as fast or impressive as what we had before, but it hopefully would do the job. (At least it looked like we had the strongest kick in the entire humanoid league!)

Thirty minutes before the start of the game, we realized that the lighting conditions on the actual field differed again from what we used to calibrate the computer vision cameras and that DARwIn could not see the ball! Last-minute tweaking did not help much but the game had to begin. What a disaster!

The robots were in position. You could feel the tension in the air. Striker 2B was having a difficult time locating the ball and when it did, it dribbled it towards the goal and it missed. It didn’t really kick the ball, but pushed it with its toe instead because it couldn’t accurately see the location of the ball and didn’t know when to give the full kick. The robots from TKU took small but quick steps, intercepting the ball and kicking it towards our goal. Unfortunately, our goalkeeper — though it had an impressive pose — was essentially a sitting duck and could not block the ball. Score 1:0. You could actually see from its body language that 2B was struggling to recognize its surroundings and the ball. The light was reflecting off from every direction, confusing him.

Strategy meeting before the game.

The second half started and striker 2B got tripped by the

Team TKU robot and fell face forward. You could see and hear the impact it took from the fall. Even with the protective guards on its chest, the inertial force from the mass of the cameras mounted on the head caused them to shift. The pan and tilt motors used to orient the camera did not work anymore! While striker 2B was trying to get up, Team TKU scored another goal. DARwIn 2B tried to run back to block the kick, but fell forward again, and completely lost its head (camera). DARwIn was now playing blind! DARwIn was walking around in circles, headless, trying to understand why everything was pitch black. The game ended, with a score of 2:0. With all A 4 AM repair job in the dorm. that went wrong, at least we were lucky that only two goals were scored.

After the game, we tried to fix the pan and tilt unit, but decided to just bolt the camera directly to the chest. DARwIn 2B no longer had a neck and would need to move its upper body to look around. It was sad to see DARwIn fall and break its neck, but it could have been worse.