Design and implementation of a ball-driven omnidirectional spherical robot

• Design of a singularity-free omnidirectional spherical robot is reported.
• Its dynamic motion model is derived.
• Empirical design realization issues are addressed.
• Experimental evaluation of the robot is performed.

We designed and implemented a novel omnidirectional spherical robot. Instead of using wheels or flywheels, a driven ball is installed inside the spherical shell and driven by two orthogonally-mounted rollers; thus, the omnidirectional mobility of the robot with no singularity can be achieved by simple forward kinematic mapping. The dynamic model of the robot is derived, and effect of the model's parameters is evaluated in simulation and discussed. The simulation results also serve as the design guideline for building the empirical system. Several design issues are addressed to ensure the robot's proper development. Finally, the spherical robot is built, and its performance is quantitatively and experimentally evaluated, thus proving its omnidirectional and trajectory-controllable mobility.