Analysis, design, and control of an omnidirectional mobile robot in rough terrain

Abstract

An omnidirectional mobile robot is able, kinematically, to move in any direction regardless of current pose. To date, nearly all designs and analyses of omnidirectional mobile robots have considered the case of motion on flat, smooth terrain. In this thesis, an investigation of the suitability of an active split offset caster driven omnidirectional mobile robot for use in rough terrain is presented. Kinematic and geometric properties of the drive mechanism are investigated along with guidelines for designing the robot. An optimization method is implemented to explore the design space. These analyses can be used as design guidelines for development of an omnidirectional mobile robot that can operate in unstructured environments. A simple kinematic controller that considers the effects of terrain unevenness via an estimate of the wheel-terrain contact angles is also presented. It is shown in simulation that under the proposed control method, near-omnidirectional tracking performance is possible even in rough, uneven terrain.