The CMU Robotics Institute has posted a new research paper (PDF format) that proposes an unusual locomotion method for legged robots. Ravi Balasubramanian, Matt Mason and other researcher are attempting to solve the problem of a high-centered robot that has become stuck in rough terrain without any contact between the robot's legs and the ground. Their solution? The robot can use its legs as reaction masses to produce "attitude oscillations that result in incremental translation". They've tested the new locomotion method using RHex as well as their own two-legged "Rocking and Rolling Robot".