Ear-based exploration on hybrid metric/topological maps

In this paper we propose a hierarchy of techniques for performing loop closure in indoor environments together with an exploration strategy designed to reduce uncertainty in the resulting map. We use the generalized Voronoi graph to represent the indoor environment and an extended Kalman filter to track the pose of the robot and the position of the junctions (vertices) of the topological graph. Every time a vertex is revisited, the robot re-localizes and updates the uncertainty estimate accordingly. Finally, since the reduction of the map uncertainty remains one of the main concerns, the robot will optimize its schedule of revisiting junctions in the environment in order to reduce the accumulated uncertainty. Experimental results from a mobile robot equipped with a laser range-finder and results from realistic simulations that validate our approach are presented.