A new driving mechanism is introduced for an omni-directional mobile robot with three ball wheels. This driving system overcomes to troubles arise from using traditional omni-wheels such as, vibration, inappropriate to employ in outdoor applications and, limited load capacity. The kinematics of the propulsion system with focus in the relation between wheels angular speeds and robot velocity is described. Then, the kinetic behavior equivalent to the kinematic description is developed. At last, using two different trajectories the overall motion of the system and torques applied to the actuators are simulated.