CMU robot soccer team has a big leg up on competition



The U.S. men's soccer team might be considered underdogs in the World Cup, but a robot soccer team from Carnegie Mellon University is confident it can take first at this month's RoboCup 2010 world championship in Singapore.

The CMDragons, a team of five wheeled robots standing less than 6 inches tall in the shape of cylinders, will look to claim its third championship in five years competing against opponents from such countries as Brazil, Iran and Thailand at the world's largest robotics and artificial intelligence event.

"I expect to finish first," team leader and Carnegie Mellon computer science professor Manuela Veloso said. "I don't see any reason why we won't win."

Dr. Veloso and the rest of the Carnegie Mellon team are expecting an algorithm developed for computer science student Stefan Zickler's Ph.D. thesis to give the CMDragons the edge at RoboCup.

Instead of the team's old strategy of planning a set of plays for the robots to execute -- like American football -- Mr. Zickler created an algorithm based on the principles of physics that allows the robots to analyze situations, evaluate the different options available to them and pick the best one. The robot's decision-making process happens at a speed of 60Hz -- or 60 times a second. The result is a considerable amount of ingenuity on the robots' part.

"The robot, in its mind, essentially, during the game, is predicting 'What would happen if I were to do this?' 'What would happen if I were to do that?' and then comes up with new strategies on the spot," he said. "We're not writing [code telling the robot what to do] anymore."

Dr. Veloso did not think any other teams will be using a similar algorithm since she has yet to see papers published on the topic.

The CMDragons showed off their creative flair last week during a practice run at the team's roughly 15-foot-by-20-foot playing field, which sits amid a room filled with computers and spare plastic parts in Carnegie Mellon's Gates Center for Computer Science.

At one point during the demonstration, one of the CMDragon robots lined up in the corner of the field to play the orange golf ball back into the game. It turned slightly to the right, seemingly scanning the field for open teammates, before chipping the ball in front of the goal to a teammate, who knocked the ball into the net in the blink of an eye.

The physics algorithm may allow for spectacular goals, but it is not always foolproof.

The CMDragons used a preliminary version of the algorithm during last year's competition and easily defeated most teams before a meltdown in the tournament quarterfinals.

"We had a pretty horrible glitch last year where our robots became blind," Mr. Zickler said. "We would crash into [our opponents] a lot because we didn't see them, and the referee gave out yellow cards until we only had the goalie left on the field. A minute before the end of the game, the other team finally eventually scored on us. And that was just with us having a single goalie."

Carnegie Mellon also will field a team of 22-inch-tall humanoid robots in the tournament's Standard Platform League. The humanoid robots walk on two feet -- which slows the speed of the game considerably -- can speak while playing, and use landmarks on the field to determine their position.

Dr. Veloso helped create the RoboCup competition more than 10 years ago, although she said robot soccer was already popular in Japan at that time. The "beautiful game's" popularity around the world was a major factor in choosing soccer as the game on which the competition would be centered, according to Dr. Veloso.

The competitive atmosphere at RoboCup -- as well as the event's eventual goal of fielding a robot team that can defeat the human World Cup champions by 2050 -- continues to fuel advancements in robot technology, she said.

Teams keep such ideas as the physics-based algorithm tightly guarded before the competition, but later publish information online and in research papers at academic conferences, which benefits the entire research community, according to Somchaya Liemhetcharat, a graduate student in robotics who works with the humanoid robots.

Soccer is an especially useful competition for robots because it features a constantly changing environment in which the outcome of every action is uncertain, and forces robots to cooperate with one another. All of those factors mean that technology developed for RoboCup has several real-world applications.

"One crucial real-world application is a team of robots extinguishing a fire," Dr. Veloso said. "A fire is very dynamic, the wind is going, the fire is changing [its location]." Robots would need to consider such factors as how wind affects the fire, the type of trees, and the speed at which the fire is spreading to cooperate in extinguishing it, she said.

Technology developed through RoboCup could also be used for robots to manage large crowds at concert venues or to regulate traffic.

The Carnegie Mellon team has been working an average of 10 hours a day per person since mid-March to prepare for the tournament.

"It's a lot of time. It's fun. Very exhausting," said Cetin Mericli, a Ph.D. candidate in robotics at Carnegie Mellon who taught humanoid robots how to walk by using a Wii video game controller to correct their motions.

It's frustrating at times, and the pressure to win is great.

"You have this responsibility," Mr. Mericli said, pointing at the mantel displaying about 20 trophies earned by Carnegie Mellon teams at RoboCup competitions. "You need to keep [the trophies] increasing."


Chris Merriman: cmerriman@post-gazette.com or 412-263-2193. First Published June 14, 2010 4:00 AM


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