Hierarchical Learning of Navigational Behaviors in anAutonomous Robot using a Predictive Sparse DistributedMemory

  • Authors:
  • Rajesh P. N. Rao;Olac Fuentes

  • Affiliations:
  • The Salk Institute, Sloan Center for Theoretical Neurobiology and Computational Neurobiology Laboratory, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA. E-mail: rao@salk.edu;Centro de Investigación en Computación, Instituto Politecnico Nacional, Mexico D.F. 07738, Mexico. E-mail: fuentes@jsbach.cic.ipn.mx

  • Venue:
  • Machine Learning - Special issue on learning in autonomous robots
  • Year:
  • 1998

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Abstract

We describe a general framework for learningperception-based navigational behaviors in autonomous mobile robots.A hierarchical behavior-based decomposition of the controlarchitecture is used to facilitate efficient modular learning. Lowerlevel reactive behaviors such as collision detection and obstacleavoidance are learned using a stochastic hill-climbing method whilehigher level goal-directed navigation is achieved using aself-organizing sparse distributed memory. The memory is initiallytrained by teleoperating the robot on a small number of paths withina given domain of interest. During training, the vectors in thesensory space as well as the motor space are continually adaptedusing a form of competitive learning to yield basis vectors thatefficiently span the sensorimotor space. After training, the robotnavigates from arbitrary locations to a desired goal location usingmotor output vectors computed by a saliency-based weighted averagingscheme. The pervasive problem of perceptual aliasing in finite-orderMarkovian environments is handled by allowing both current as wellas the set of immediately preceding perceptual inputs to predict themotor output vector for the current time instant. We describeexperimental and simulation results obtained using a mobile robotequipped with bump sensors, photosensors and infrared receivers,navigating within an enclosed obstacle-ridden arena. The resultsindicate that the method performs successfully in a number ofnavigational tasks exhibiting varying degrees of perceptualaliasing.