Narrative Fallacy writes "The Cornell Ranger robot has set an unofficial world distance record by walking nonstop for 45 laps — a little over 9 kilometers — around the Barton Hall running track in an event to to show off the machine's energy efficiency. Unlike other walking robots that use motors to control every movement, the Ranger emulates human walking, using gravity to help swing its legs forward. The Robot alternately swings two outside legs forward and then two inside ones and although the robot has no knees, it has feet that can be tipped up and down, so that the robot pushes off with its toes, then tilts its feet upward to land on the heels as it brings its legs forward. The Robot is steered by a hobby remote control which biases the steering to one side or another by lifting one of the four feet slightly. 'We've just moved into this world of electromechanical devices, and to make something this robust is a big achievement,' said Andy Ruina, Cornell professor of theoretical and applied mechanics. 'We've learned tons about what it takes to make walking work.'"