A novel spherical wheel driven by Omni wheels

A novel combination of Omni wheel and spherical wheel unit (CWWU) is presented in this paper, and its operating principle is basically a spherical wheel driven by two perpendicular pairs of Omni wheels. Thus, a CWWU base robot can perform the static and dynamic balancing function that a single wheel with inverse mouse-ball drive developed by Carnegie Mellon University (CMU) can achieve. The previous rolling/balancing machines cannot immediately drive in a given direction without first re-orienting the drive mechanism. The major feature of the presented CWWU base robot and the CMU robot is that both of them can move directly in any direction. As compared the Omni wheel base robot with the proposed one, the main drawback of the Omni wheel robot is the cancellation of opposite portion of the driving forces. Moreover, the CWWU base robot has several exclusive features which can resolve some problems inherited in the CMU robot. Especially, the simultaneous demand of both a high-friction and low-friction material for the spherical ball is a compromise needed to make for the CMU robot, but not for the proposed CWWU base robot.