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Robots Invade U of I Campus

CSL Researchers Also Control and Coordinate Robots in New Mexico

By Doug Peterson

March 2005

Animated robots are dominating the big screen, thanks to the movie Robots. But if you want coming attractions of what the future has in store for real robots, the University of Illinois is the place to be. In fact, coming this summer, don't be surprised if you see a U of I professor zipping through campus on a Segway, followed close behind by a robot -- also riding on a Segway.

Mark Spong, CSL professor and interim head of general engineering, is planning to take this campus ride with a robot in the summer. He is spearheading several projects on robotics, including one in which students create robots that can ride the two-wheeled, self-balancing vehicles known as Segways.

In another project, Spong and graduate student Oscar Martinez-Palafox have developed ways to control groups of robots long distance over the internet. Using a joystick interface at the U of I, they can control a team of robots located over 1,200 miles away at the University of New Mexico in Albuquerque.

Controlling single robots over long distances using the internet is actually nothing new. But the U of I team is one of the few in the country developing ways to control and coordinate multiple robots over the internet.

To perform certain tasks, such as picking up and moving a large piece of equipment, teams of robots must be able to move together in a fixed formation. This means the operator must be able to control them as a group, rather than individually.

Another unique feature of the U of I research is the use of “force feedback,” in which the operator actually feels the forces that the robots encounter. In other words, if a robot in New Mexico bumps into a wall, the operator back in Illinois feels resistance on the joystick.

Spong and Martinez-Palafox have successfully controlled the team of robots in New Mexico, but they’re still dealing with some of the unique problems posed by the internet.

According to Spong, using the internet is much cheaper than using an expensive, dedicated communication line to control robots at long distances. However, there are unpredictable delays on the internet and the risk of losing packets of information -- all of which can make a robotic system highly unstable.

“Delays are frustrating when you’re downloading a file,” said Spong. “But they’re disastrous if you’re trying to control something in real time.”

To deal with this problem, Spong and Martinez-Palafox are developing new control algorithms that can guarantee a certain level of performance when using an unreliable communication channel such as the internet.

“Even delays on the order of a few milliseconds can cause the control system to be unstable, unless you use the kind of computational methods that we’ve developed,” said Spong.

This research, sponsored by the National Science Foundation, NASA and the Office of Naval Research, could help in developing ways to control robots in space from Earth or undersea from surface ships. Currently, he pointed out, robots that do construction in space must be controlled by astronauts because of time delays when trying to control them from Earth.

“NASA tried controlling the robots from the ground in the past, but the time delays were killing them,” he said. “But now they’re trying to get back into that because we now know how to solve some of the delay problems.”

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