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CU's RoboCup team finishes third, falling victim to a 'stall' tactic

By Bill Steele

After two straight years as undefeated and almost unchallenged champions, Cornell's Big Red team returned from this year's Robocup competition with only third-place honors. While Big Red's faster, stronger and more mobile robots clearly outplayed most others, the team lost in the second day of playoffs to an oddball strategy employed by the Field Rangers, a team from Singapore.

In the international Robocup competition, teams of small robots play soccer under computer control, without human intervention. The game is a test of artificial intelligence. In the "small robots" league where Cornell competes, the robots are about the size of a soccer ball and play on a field the size of a table tennis table, using a golf ball as the ball. Cornell entered for the first time in 1999 and handily took first place that year and again in 2000. Raffaello D'Andrea, Cornell professor of mechanical and aerospace engineering, coaches the team and attributes its success to the fact that the team includes mechanical and electrical engineers as well as computer scientists.

In the 2001 competition, held in Seattle Aug. 2-10, the Big Red robots easily advanced to the playoffs, and in their first quarterfinal game against the Portuguese team 5DPO, the European champions, Cornell won 2-1, partly by adopting a strategy to overcome the powerful kicking mechanism of the Portuguese robots and partly because the Portuguese robots were too "physical," causing one their team to be ejected by the referee.

But in the semifinal, the Field Rangers employed a frustrating "stall" technique, in which they blocked the ball between a robot and the wall and simply waited. The 20 minute match was reduced to about three minutes of actual play. The Field Rangers scored once during the first half when the ball momentarily became hidden from the Cornell vision system, and after a scoreless second half, the Field Rangers were the winners, 1-0. A rule change is contemplated to disallow the stalling strategy in the future.

In the consolation game for third place, Cornell played the FU-Fighters from the Free University of Berlin, the team they defeated last year to win the championship. Despite several technical glitches, some apparently brought on by lack of sleep for the human members of the team, Cornell squeaked through with a 6-5 win, scoring the winning goal in the last 20 seconds of play.

In the final, the Lucky Star team, also from Singapore, overcame the Field Rangers 3-0.

"Clearly we are disappointed that we did not bring home the first place trophy this year," D'Andrea said in his online report from Seattle. "On the other hand, our team was the talk of the competition; our passing play amazed the crowds and the competitors and paved the way for the future of RoboCup. We had two objectives this year: to play well and to win the competition. We certainly achieved the first."

Student team members who traveled to Seattle were Michael Babish, Tim Chung, Kent Cseh, Gonzalo Dominguez, Pritam Ganguly, Mae Huang, Brett Nadler, Oliver Purwin, Thibet Rungrotkitiyot, Anurag Sharma, Christian Siagian and Will Stokes.

D'Andrea's detailed reports are at

August 16, 2001

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