• Michael Babish (CS)
• Tim Chung (MECHE)
• Kent Cseh (EE)
• Raffaello D'Andrea (MECHE/AE/EE/CAM/TAM)
• Gonzalo Dominguez (EE)
• Pritam Ganguly (TAM)
• Mae Huang (EE)
• Brett Nadler (MECHE)
• Oliver Purwin (MECHE)
• Thibet Rungrotkitiyot (CS/EE)
• Anurag Sharma (MECHE)
• Christian Siagian (CS)
• Will Stokes (CS)

The first priority is of course computer vision: Thibet and Christian, with help from the MECHEs, begin to set up the vision system. After more than one hour of continuous checks and re-checks, however, we still cannot obtain a valid video signal from the camera. My worst nightmare is starting to come true: our ONLY non-redundant system, the Matrox Frame Grabber, does not seem to be responding to our requests for images. A hunch from Gonzalo pays off: the telephoto lens was not correctly mounted to the base system, resulting in loss of video signal. After this minor setback, Thibet and Christian are able to bring a preliminary version of the vision system up to speed by lunch-time, and spend the rest of the afternoon finalizing the multitude of vision calibration settings.

The first game against the Canucks is disappointing: the Canucks are not capable of overcoming last minute wireless and vision problems, and are thus not capable of mounting any type of defense against our team. The ten goal mercy limit is quickly reached, even with our speed and acceleration gains drastically lowered, and most of our offensive strategies disabled.

FINAL SCORE: Cornell (USA) 10, Canucks (Canada ) 0.

The second game against the Spaniards is definitely not a repeat of the tournament opener. Rogi, RoboCup participants since '97, have a seasoned defense. The Cornell passing, dribbling, and shooting game is too much for Rogi, however, and the first goal is quickly netted. This is quickly followed by a second and third. The half ends with Cornell up 6 to 0. The second half is a repeat of the first, and Cornell reaches the ten goal margin half-way through the period. The mercy rule is once again invoked, and the game goes in the record books as a 10 to 0 Cornell victory.

The Cornell team goes through their warmup routines (see links), and pass the preliminary tests with flying colors. We are ready! The game begins, and immediately the Cornell team begins to have control problems; the robots are not responding, and behave erratically. A wireless problem! We still manage to score a goal in the first minute of play. We cannot understand what the problem is: the system was fully operational before the game began. The Cornell team continues to play crippled, and are forced to call a time-out. An exhaustive search of the premises turns up empty: no-one is transmitting at 433 MHz, the frequency allotted to the Cornell team for the game. This is a complete mystery for us: we determined the other day that our antenna-less robots should only be able to receive commands within a very tight radius (less than 5 meters). The Cornell team is not the only team with control problems: Sharif is also behaving erratically. We become suspicious, and explore a possibility that should have perhaps been obvious all along: Sharif is inadvertently using the same frequency as we are. Sure enough, this was the problem. Given that we are ahead by one goal, however, no punitive action is taken against Sharif, and the game continues after the appropriate changes have been made to the wireless system.

Six minutes of play have elapsed. With our robots fully under control, it does not take us long to score eight goals before the end of the half. In fact, Cornell has an opportunity to score a game ending tenth with three seconds left on a free kick, but a mistyped key to begin the play leads to a wasted opportunity. Cornell scores within the first minute of the second half to end the game.

FINAL SCORE: Cornell (USA) 10, Sharif (IRAN) 0.

The game begins, and it is clear that the Melbourne team has decreased their "politeness factor" in order to throw us off our passing game; in more technical terms, they have turned off their obstacle avoidance when in the vicinity of the ball. They also position one of their players behind our goalkeeper in an attempt to interfere with it (our goalie comes way out of the net to cut off the angle). Their strategy is effective in stopping our precision passing, but soon results in a yellow card infraction: one of their players pushes our goalie by over a foot. Even with the rough play, Cornell is able to score its first goal on a penalty shot at approximately the 6th minute of play. The rough play continues, and Melbourne is eventually awarded a red card, and as a result, must pull out one of their players and finish the game with only four robots. More importantly, they must enable their obstacle avoidance once again to prevent more yellow and red card infractions. The Cornell team now takes control of the game, and scores another goal before the half.

The second half finds the Cornell team executing its precision passes and shots. Two goals are scored on incredible pass-shot combinations (see the play-back files), to the amazement of the crowds. The game continues with Cornell dominating the play. With three minutes remaining in the game, Cornell scores its seventh goal, enough to eliminate Melbourne from the competition. Melbourne calls a time out, and starts to make some desperate changes to their code in order to score at least one goal. When the final whistle blows, the Cornell team finds itself with an 8-0 victory and a first place seeding in the final eight. It is unfortunate that the Melbourne team is once again eliminated by Cornell in round-robin play (see th '00 diary for details); they are certainly a top eight team, perhaps even top four. Unfortunately for them, their team did not really show up until the final game of the round robin against Cornell, and their 4-1 victory against Sharif (Iran) should have been a 10-0 rout.

FINAL SCORE: Cornell (USA) 8, RooBots (Australia) 0.

7:45 AM. Alan Alda and the Scientific American Frontiers crew arrive, and wire us up for the on-game commentary; Alan and I will be sitting in the middle of the stands during the game, providing game analysis. We go through our pre-game warmup, with no apparent problems.

8:00 AM. The whistle blows to begin the first of the RoboCup 2001 quarter final matches. The 5DPO strategy becomes immediately obvious: play a conservative defense, and dump the ball upfield hoping for a scoring opportunity to emerge. The Portuguese are also quite physical, and are awarded a yellow card within the first five minutes of play. Our modifications to guard against their powerful kick work like a charm: all of their free-kick opportunities are guarded by our midfielder, who wisely positions itself in front of the free-kick area, and not the ball, during game play. Their dump and chase strategy, coupled with their physical play and a strategy error in the part of our goalie lead to a surprise 5DPO goal with minutes left in the first half, even though most of the play is in the midfield and in their zone. The last few minutes tick down, and the first half ends 1-0 for the Portuguese.

HALF-TIME. We decrease the roaming radius of the goalie, a temporary fix for the strategy bug we have discovered in our current goalie code. We decide to not make any more changes to our system; our play is strong, and only thwarted by their physical play. We reason that is only a matter of time before we either score, or one of their players is ejected for rough behavior. We inspect the dribbler bars of our players, and find little chunks of aluminum embedded in the rubber, compliments of the 5DPO rotating kicker.

8:40 AM. The second half is essentially a continuation of the first. Within three minutes of play, a 5DPO player is awarded a second yellow card, and automatic expulsion, for rough play. The crowd waits in anticipation as Gonzalo aims the robot for the free kick in front of the television cameras. He does not disappoint, and Cornell scores to tie the game. With three minutes left to play, 5DPO, a player short, receives another yellow card for rough play. They call a time out and modify their system in order to avoid an additional red card and mandatory expulsion. The Cornell team quickly takes advantage of the situation, and score a second goal with time running out. The final whistle blows: Cornell advances to the semi-finals, to be played at 3:00 PM.

We immediately hold a team meeting to discuss changes that need to be made to the system in preparation for the semi-finals. In particular, we all agree that the goalie code must be repaired. By 11 AM, we find out that the Field Rangers have upset the RoboRoos 1-0 in the other group A quarter final match. We are somewhat relieved: the Field Rangers have virtually no offense. We are somewhat dismayed, however, to find out how the Field Rangers have won the match. Their strategy against the RoboRoos was to position themselves between the ball and the wall, and preventing play from occurring. Continuous repositioning by the referee simply resulted in the Field Ranger robot moving back to block the ball. As a result, the twenty minute match turned into a three minute match in terms of game play, and vision glitch in the Australian system was capitalized by the Field Rangers.

3:00 PM. The game begins on time, and to the frustration of the crowd, the Field Rangers play the same stall tactic that they employed against the Australians. The Cornell team has various scoring opportunities, but they cannot capitalize. With approximately three minutes left to play, the unthinkable happens: a ball occlusion that occurs with our robot having possession of the ball, coupled with a Field Ranger player being in the right place at the right time to position itself in the occluded position result in the Cornell robots thinking that the ball is somewhere where it is not (when the ball is occluded, our global vision system cannot see it, and as a result, we must predict where it is most likely to be). The Field Ranger player finds itself with the ball in front of the Cornell net with our players guarding against a shot from a different part of the field. The Field Ranger player simply pushes the ball into the open net.

The second half is a repeat of the first; most of the time is spent with the ball on the sides of the playing field, with the Field Rangers running precious clock time with their stall tactic. Cornell has several scoring chances, but cannot capitalize. The game finishes 1-0, and for the first time in Cornell RoboCup years, the Cornell team loses a RoboCup match, and is knocked out of the finals. The team is clearly upset; we were clearly the better team, but could not display our skills with only a few minutes of actual game time. Everyone in the crowd and the RoboCup community is talking about how a rule change must take place from preventing this to happen again, but of course, it is too late for us now.

At the half, we decide to not change the system in any way; we are playing well, and their goals are mainly due to human error. The half resumes, and we quickly score the equalizer on a passing play. We score three more goals to take a 5-2 lead. But once again, we squander the goal cushion. The FU-Fighters score on a legitimate passing play from the corner (the first time this tournament that the Cornell team is scored upon during "normal" play), and follow this up with two more goals: the first against non-moving Cornell robots when the vision system is inadvertently turned off before play, and immediately the second immediately afterwards when the wireless system is inadvertently turned off before play. With 22 seconds left in the game, two FU-Fighter players find themselves in their defense zone, and the Cornell attacker quickly takes advantage of this situation by shooting at the net: the penalty for this infringement is a penalty shot. The FU-Fighters substitute their goalie for a faster, but somewhat uncontrollable, prototype player, in preparation for the shot. The Cornell player is set up for the penalty shot, as is the German goalie. The whistle blows. The German goalie rushes the ball hoping to cut off the angle before the kick. The Cornell players kicks the ball towards the corner. This time, the ball gets there first. Cornell 6, FU-Fighters 5. The play resumes, but time quickly runs down. Cornell takes third place in RoboCup 2001.

(Written by Will Stokes, Michael Babish, and Nicole Schlegel)

• Testing/using the robots without turning them on was a bad idea. While in concept the self-powered PID's were clever, we should have tested this back in the lab and not in our final game.
• Assuming our robots always have possession of the ball made sense, because that *was* what were attempting to do. However, in retrospect it makes a little sense to make our system more "robust" and have the goalie only try to reset the ball position when the ball is actually lost.
• Arrogant brick play was awesome in the lab. We were never scored upon by stationary obstacles! However, more testing should have been done with moving robots before using this play in the final game.
• Passing was awesome. Having the robots get into position ready for a pass behind the goalie worked like a charm. However, next time around we should program the robot which has the ball to kick it to the robot that is supposed to receive the ball. Despite many attempts, pleading to the robot during game play had no effect.
• Dribbling the ball up the field was an awesome idea, and much of the time it worked very well. However, before our next game we should remove the calls to chip-kick the ball over an opponent every time we get stuck, since the chip kick was never actually implemented on the robots.
• The robust mechanical design of the robots was superb. They never broke, and when pushed against never moved. However, after watching portions of the RoboRoos-vs-CMU game, adding ejecto-parts would have helped us achieve more penalty shot opportunities.
• When down in the end of the game, we should have made use of the explode option in the destination class.
• Putting the "Start Game Key" next to the "Turn Vision Off Key" was a bad idea.
• Our assumption that our code was "bug-free" was a poor one. In retrospect, actively testing and debugging our system should have been a priority.
• Our operator (team member that starts/stops the robots) should not laugh when s/he sees parts of the opponent robots fly off the field. They may actually be our parts.
• Our operators should be trained in anger management. Not only is it a bad idea to taunt the ref because he has the power to eject us, but dude, he's the one holding a stick.
• NB: RoboCup crowds will do a wave. Who would have ever thought... and can we use this to our advantage?