Omni-drive Robot Motion on Curved Paths: The Fastest Path between Two Points Is Not a Straight-Line

Abstract

Omni-drive systems operate by having individual wheels apply torque in one direction in the same way as a regular wheel, but are able to slide freely in another direction (often perpendicular to the torque vector). The key advantage of omni-drive systems is that translational and rotational motion are decoupled for simple motion. However, in considering the fastest possible motion this is not necessarily the case. In this paper, we review all the current popular designs of omni-drive transport systems, and compare them in terms of practical and theoretical considerations. We then present a kinematic analysis that applies to two major omni-drive robot vehicles classes, for any number of wheels. Finally, we show that for three-wheeled omni-drive transport systems and certain ranges of trajectories and starting conditions, a curved path can be traversed faster than a straight-line path, we confirm this result experimentally.