Design and Verification of an Adaptive Control Algorithm for a Redundantly Actuated Omnidirectional Mobile Platform

This paper discusses the design and control of a new ball-wheel drive mechanism for a robust omnidirectional wheeled mobile platform. This platform, integrated with a manipulator, is designed for use in highway maintenance and construction, which is a generally unstructured and congested environment. The proposed ball wheel mechanism can move in all directions on the plane, instantaneously and isotropically. For accurate motion with parametric uncertainty in the dynamic model, an adaptive controller is applied to the trajectory tracking control of the single ball wheel platform. The redundant drive system of the ball wheel mechanism changes its configuration according to the heading direction by changing the contact pressure between the drive wheel and the sphere. A weighted torque optimization method is used for the resolution of redundancy and for smooth reconfiguration. The experimental results demonstrate the effectiveness of the proposed method.