Optimal Isotropic Characteristics of a Mobile Robot with Three Active Caster Wheels

This paper presents both local and global isotropy analysis of a fully actuated caster wheeled omnidirectional mobile robot (COMR). No assumption is underlaid for the ratio of the steering link offset to the caster wheel radius. First, with the characteristic length introduced, the kinematic model of a COMR is obtained based on the orthogonal decomposition of the wheel velocities. Then, the local and the global isotropy indices are defined and used to determine the optimal design parameters in terms of the characteristic length and the steering link offset.