Symbolic trajectory description in mobile robotics

Gilbert Pradel (gpradel@lsc.univ-evry.fr)
Philippe Hoppenot (hoppenot@lsc.univ-evry.fr)
Laboratoire Syst_emes Complexes, Université d'Evry Val d'Essonne
CNRS FRE 2494
40,rue du Pelvoux, CE 1455 Courcouronnes
91020 Evry cedex. FRANCE

Abstract. Autonomous mobile robot navigation systems are based on three principal kinds of techniques: map-based navigation, map-building-based navigation and mapless navigation. We propose a method for symbolic trajectory description in unknown indoor environments. The chosen form uses a panoramic description called fresco. The method uses distance measurements from a 2D laser range finder, digitises the robot's visibility area, eliminates superuous data and reorients their presentation. The landmarks are then extracted and organised into the fresco which is validated by means of neighbourhood rules. As the robot moves in the environment, the frescoes are created and both the amount of new information a fresco carries out and its position in relation to the preceding ones are evaluated by means of two criteria. Only frescoes selected as enough informative are stored to describe the robot's route.

Keywords: Autonomous mobile robot, environment symbolic description, symbolic navigation.