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rogrammed to recognize orange soccer balls, a USC team of
robot athletes might prefer to attack a wall or a grad
student's leg.
But such are the problems to be worked out when putting
together one of the first American robot soccer teams--to
compete with four clubs next week in the first annual RoboCup
(Robot World Cup) in Nagoya, Japan.
Five players, built and programmed by a team of USC
professors and students, will play soccer without human
assistance.
"Our robots are completely on their own," said student
Rogelio Adobbati. "If they score, it's on their own merit. If
they score on their own goal, it's their own fault. We try to
blame them instead of blaming ourselves."
Adobbati, a student clearly accustomed to having his
legs attacked by Chihuahua-sized machines, nudges a defender
named Marge away. His frustration mounts, though, when Marge
and her teammates repeatedly slam head-first into walls or
begin binges of spinning in circles.
"It's like when you want a dog to fetch a stick and it
just stares at you," Adobbati said.
The robots are programmed to sense where the ball is and
to chase it into the goal. They're supposed to cooperate with
teammates to outmaneuver opposing players.
Coaches will not tolerate ball hoggers.
* * *
"If one guy sees that the other team member already has
the ball, he will not chase," said Wei-Min Shen, the computer
science professor heading the project.
The complexity of such a task is extraordinary. Just
getting a robot to distinguish between a soccer ball and a
human leg requires months of programming, Shen said.
Sometimes their eyes detect the red hue in flesh and mistake
it for the orange in a soccer ball.
"Luckily, it's so small, it can't do any harm," Adobbati said.
To build the robots, the scientists took
radio-controlled toy trucks and souped them up--essentially
giving an eye and brain to each.
The eye is an off-the-shelf digital camera that senses
color and shape. With the brain--a laptop computer mounted to
the player's back--it can gauge distance by the relative size
of an object in its field of vision.
The robots move on oversized spherical truck wheels that
spin individually, allowing the robots to twirl with speed
and agility. Shen estimated that each android costs about
$900.
The USC team--two attackers, two defenders and a
goalkeeper, all named for characters on "The Simpsons"
television series--will play four games at the
corporate-sponsored tournament. Since the androids quickly
drain power from their batteries, the games last only 10
minutes.
* * *
In Shen's league, the medium-sized division, the teams
will come from universities in Australia, the United States
and Japan. Shen and eight graduate students began working in
their free time on the project several months ago. USC's
Information Science Institute had decided to fund the team
after its students placed second in an unrelated robot
competition last year, Shen said.
Beyond prestige, there is no reward in winning the
RoboCup. But the tournament is connected to the International
Conference on Artificial Intelligence and is considered a
major event in this scientific field, Shen said. After the
tournament, each team will share its experiences and its new
technology with the others at a workshop.
On USC's team, each player is programmed to perform a
specific task on a 5-by-8-meter field. Maggie the goalkeeper,
for example, has an eye on its side, so it is more capable of
moving back and forth laterally to prevent goals.
Experts say that combining the more abstract field of
artificial intelligence with the real-world mechanics of
robotics is a trying task.
"One of the holy grails in artificial intelligence is to
build a robot that can do the things that we do," said UCLA
professor Richard Korf.
Korf said that building and programming robots to do
simple tasks that a child easily performs can be as hard as
teaching them to be a chess master.
"In some ways chess was easy," Korf said. "[That] world
was very predictable. [But] if you play soccer, you know when
you kick the ball it doesn't exactly do what you want."
Soccer players also deal with the added element of
time--they have to make decisions in split-seconds. And
again, they have the problem of recognizing the ball, the
goal, teammates and opponents.
* * *
Shen, who has worked in the field of artificial
intelligence for 14 years, is determined to overcome
real-life obstacles. "It's more challenging," he said. "I
always think that to really understand intelligence you have
to try the real thing. You have to deal with sensing
uncertainty or uncertainties in action."
Shen hopes to someday build a robot that learns like a
child, but can go where no human could--like the Los Angeles
sewer system. A year ago, he proposed to the county
Sanitation District a robot design called the "pipe fish,"
which would drift or swim down massive sewer lines to detect
corrosion.
Sewage always fills these trunk sewer lines, with no way
to check for damage, said Dave Greenwood, a supervising
engineer at the agency.
Engineers thought the idea was clever, but county
supervisors decided that the project would be too costly and
postponed the proposal, Greenwood said. He added, "It's
possible that we'd throw it in and never find it again."
Now, Shen, like an overzealous father, devotes all his
time to his soccer team. "I feel like they're my babies," he
said. And when his babies get a little deranged and go for a
human leg, he says he's nothing but proud. "No one else is
doing it."
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