Home Front Page Meet RHex: the robot that jumps, flips, and does pull-ups


University of Pennsylvania scientists have potentially solved one of the biggest problems in countering rubble in rescue missions by creating a new robot that is able to jump and flip over obstacles. The new robot, named RHex, is a six-legged robot. Instead of a more common robot-look, the robot has curved legs, which the team says allow it to more easily deal with difficult objects to climb over. In a video on the Boston Dynamics website, which created the robot, Rex scrambles over a variety of natural obstacles, including a log. At one point the robot even flips upside down, but rather than flail helplessly as one might expect, it simply continues on as if it were still right side up.

“Legs have an advantage over wheels when it comes to rough terrain, but the articulated legs often found on walking robots require complex, specialized instructions for each moving part,” Evan Lerner from the University of Pennsylvania said in a statement.

Graduate student Aaron Johnson and professor Daniel Koditschek from the University of Pennsylvania are working on another version of the robot, labeled “XRL,” or X-RHex Lite. This model is both lighter and more agile, allowing it to more easily circumvent the obstacles presented in a set course. XRL can execute jumps and a short series of other moves, including pull-ups. The model is ideal for testing new ways for robots to climb and jump. In a video from UPenn, the robot is seen in slow motion, allowing the viewer to better understand exactly how it works. The curved legs move in a circular motion, propelling the robot forward and allowing it to climb steps. XRL is even able to thrust itself forward in a flip to allow it to climb obstacles taller than its legs.

The team hopes in the future that the robot will become advanced enough to use it in terrain where it is difficult for humans to gain access. The scientists behind its creation suggest that in the future it could be used to zoom across long desert distances, or even climb rubble at disaster sites. With its current ability to scramble up over obstacles, that future is not that far away. RHex would be a strong asset at disaster scenes, potentially carrying a camera to allow rescuers to see more of the landscape or perhaps even transporting a small amount of supplies.