Positioning and localization system for autonomous wheelchairs

This paper presents a new positioning and localization system (PLS) designed to be installed on board of an autonomous wheelchair. Special constraints of this kind of applications make unuseful other conventional solutions that cannot be directly applied to this case, although they were the right choice in other mobile robotics fields. The system here presented makes use of artificial landmarks, specially designed to provide, with a minimum cost, full information about relative position and orientation to landmark and also its localization by means of an associated topological map; so it is possible to know absolute position-orientation of the vehicle with enough precision, even in heavily structured environments, without the uncertainty problems related with other conventional systems. An additional advantage of the navigation system here described is to be able of plan an appropriate route even in places never visited before, using for this task wireless nodes to upload to vehicle local topological maps.