A general world representation for mobile robot operations

Abstract

This paper describes a general and efficient database for representing the information of the world that a mobile robot needs to operate in a structured environment. This representation, called AH-Graph, stores both structural information about the relationships existing among the objects of the world and perceptual information about physical features of those objects. The connections between elements of the world model are qualified so that relationships of navigability, proximity, ownership, etc. can be represented. The AH-Graph also defines a hierarchy over the set of elements of the world, allowing to deal not only with single objects, but also with groups and portions of objects. These characteristics lead to an efficient storage and retrieval of the information, which is very important for maintaining a dynamic model of environment. Since the sensors are limited for obtaining structural information from the world, a human operator must be involved in the building process of the AH-Graph. A detailed description of the AH-Graph and an example of its utility for the navigation of our mobile robot RAM-2 in an indoor environment is outlined.