Body and leg coordination for omni-directional walking in rough terrain

Abstract

In this paper, we address the problem of moving a legged robot in an unknown environment according to externally provided driving commands assuming an arbitrary initial position of legs. This general problem is decomposed in three subproblems: first, decide when to lift a given leg, second, choose where to move lifted legs, and third, coordinate body and leg movements to make the robot advance in the desired direction. To solve this third problem, we extend the posture control mechanism introduced in (1) so that body movements are limited to the desired trajectory. The resulting controller performs smooth transitions between different trajectories and can cope with irregular terrain where valid footholds are scarce.