A study of autonomous mobile system in outdoor environment. IV. Sign instructed navigation and autonomous loading for outdoor transportation

For pt.III see ibid., p.485-90 (1999). This paper presents a new method for outdoor navigation and autonomous loading. The system consists of an autonomous vehicle and signs. Signs indicating waypoints and next instructions are tracked and recognized one after another by using a vision system. Once the vehicle recognizes a "loading sign", the environmental map is generated from range data obtained by an area laser radar and is processed to make a local path to the pallet which satisfies kinematics constraints of a car-like 4 wheeled vehicle. The system is adaptable to the changeable environment because transportation paths can be easily changed by altering the contents or placement of the signs. Experimental results obtained in the outdoor environment show the validity and flexibility of the system.