Feedback control of Omni-Directional Vehicles using two wheels caster type odometer

A feedback control method of Omni-Directional Vehicles (ODV) is proposed by using a caster type odometer. The odometer which is called the Two Wheels Caster Type Odometer (TWCTOdometer) is specially designed for ODVs. Driving wheels of typical ODVs are easy to slip. When an odometer is connected directly with the shafts of driving wheels, the slip of the driving wheels causes much dead-reckoning error. Thus the TWCTOdometer is attached independently to the driving wheels of the ODV in order to avoid the influence of slips of the driving wheels. The TWCTOdometer has a characteristic of passive omni-directional motion, which is to follow the omni-directional motion of the ODV. The ODV´s current position and orientation are estimated accurately from the measurement values of the TWCTOdometer. The proposed control method uses the estimated current position and orientation that allow the accurate trajectory control of the ODV along desired trajectories. Experimental results show effectiveness of the proposed control method by using the TWCTOdometer.