Researchers build jumping, flipping, hand-standing robot

Robot that could one day be used by the military or for search and rescue missions (Video below)

Researchers at the University of Pennsylvania have created a robot with six curved legs that can do a hand-stand, jump over gaps and climb over rocks.

The robot could one day be used by search-and-rescue teams or by the military in dangerous environments.

"Overall, we're really interested in making a robot that can go anywhere," Aaron Johnson, a graduate student at the university and a member of the research team, told Computerworld. "In terms of disaster areas, you're not going to have perfect stairs and perfectly flat ground. There's going to be clutter and uneven terrain. You'd need a robot that could get over all of that."

Scientists initially designed the robot, dubbed Robot Hexapod or Rhex (pronounced Rex), about 10 years ago, It's since been redesigned to be lighter and sturdier, according to Johnson.

The redesigned robot is named X-RHex Lite or XRL.

Researchers trimmed the Rhex robot from nearly 21 pounds to 16.5 pounds during the redesign process, largely by replacing metal with carbon fiber.

"The weight makes a pretty big difference when you're trying to do acrobatic leaps and jumps," said Johnson. "With any extra weight, it's going to be that much harder to jump."

University scientists designed the robot with legs instead of wheels because legs can more readily maneuver on rough terrain, climb over rocks and jump over gaps. The jointed legs required complex, specialized coding for each moving part.

Instead of using multi-jointed legs, scientists built the robot with curved, one-joint legs, which enable it to manipulate its body into hand-stands, flips and jumps.

Johnson said one of the biggest design challenges was adding what he called behavioral intelligence, or the ability to have the robot's legs, which move in different sequences, coordinated to run, jump, flip and do pull-ups.

"The way the legs work naturally help get it over the rocks but they're also useful in forward jumps," he added. "The [legs'] rolling contact allows Rhex to throw itself forward in a more effective manner. The challenge has really been trying to push as much performance out of the machine as possible, trying to get over the biggest gap or over the largest rock. How do you get the most power out of it without the robot inflicting damage on itself."

Johnson explained that having the robot throw itself over a hole in the ground or on top of a rock are "almost violent behaviors." Rhex needs to be strong enough to endure that kind of punishment without breaking a leg or damaging its body.

He added that scientists are working now on making the robot more proficient in traveling over rough terrain.

The U.S. Defense Advanced Research Projects Agency, or DARPA, funded the development of the first Rhex robot 10 year ago. The Army Research Laboratory is funding the latest reach on it.

Johnson said he estimates work on the updated robot should be complete in about two years.

The all-terrain XRL walking machine is designed to use its six semi-circular legs to climb over rubble and jump over holes. (Video: Kurtis Sensenig)

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, or subscribe to Sharon's RSS feed . Her email address is

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