The IMPASS robot will use rimless wheels with spokes that can lengthen or shorten according to terrain. IMPASS, which stands for Intelligent Mobility Platform with Active Spoke System, is under development at Virginia Polytechnic Institute and State University.
According to one of the developers, engineer Dennis Hong, the spoke wheel concept "allows multiple modes of motion, which give it the ability to stride quickly using one contact point per wheel, walk with static stability with two contact points per wheel, or assume a stable stance using three contact points per wheel."
Hong designed the system along with colleague Doug Laney.
Legs work better when negotiating very rough terrain, but are often slower than wheeled vehicles on smooth surfaces. The IMPASS system tries for the best of both worlds; the three spokes can be made to lengthen or shorten independently, allowing the robot to adjust itself to overcome obstructions. Turning can be done by varying spoke length as well.
Hong and Laney hope to complete a prototype version of the IMPASS robot early next year.
You might also be interested in this related item - the Tweel,which combines both the spokes and the tire. Here's another device that actuallymoves by adjusting spoke length - SoftRobot Powered by Shape Memory Alloy Spokes. The original story was found here.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)