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

  • 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:
  • Autonomous Robots
  • Year:
  • 1998

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Abstract

We describe a general framework for learningperception-based navigational behaviors in autonomous mobilerobots. A hierarchical behavior-based decomposition of thecontrol architecture is used to facilitate efficient modularlearning. Lower level reactive behaviors such as collisiondetection and obstacle avoidance are learned using a stochastichill-climbing method while higher level goal-directed navigationis achieved using a self-organizing sparse distributed memory.The memory is initially trained by teleoperating the robot on asmall number of paths within a given domain of interest. Duringtraining, the vectors in the sensory space as well as the motorspace are continually adapted using a form of competitivelearning to yield basis vectors that efficiently span thesensorimotor space. After training, the robot navigates fromarbitrary locations to a desired goal location using motoroutput vectors computed by a saliency-based weighted averagingscheme. The pervasive problem of perceptual aliasing infinite-order Markovian environments is handled by allowing bothcurrent as well as the set of immediately preceding perceptualinputs to predict the motor output vector for the current timeinstant. We describe experimental and simulation resultsobtained using a mobile robot equipped with bump sensors,photosensors and infrared receivers, navigating within anenclosed obstacle-ridden arena. The results indicate that themethod performs successfully in a number of navigational tasksexhibiting varying degrees of perceptual aliasing.