Lazy Reconfiguration Forest (LRF): An Approach for Motion Planning with Multiple Tasks in Dynamic Environments

Russell Gayle1, Kristopher R. Klingler2, Patrick G. Xavier2


1: rgayle@cs.unc.edu  2: {krkling,pgxavie}@sandia.gov


Arrow demo

Path traced by an arrow shaped robot. Obstacles are shown
at the time of path completion.




Abstract
    We present a novel algorithm for robot motion planning in dynamics environments. Our approach extends Rapidly-exploring Random Trees (RRTs) in several ways. We assume the need to simultaneously plan and maintain paths for multiple tasks with respect tot he current state of a moving robot in a dynamic environment. Our algorithm dynamically maintains a forest of trees by splitting, growing, and merging them on the fly to adapt to moving obstacles and robot motion.  In order to minimize tree maintenance, we only validate the task paths, rather than the entire forest. The root of the inhabited tree moves with the robot. Dynamic re-planning is integrated with tree and forest maintenance. Coupling the robot motion with the planner enables us to support multiple tasks, for example providing an "escape" path while moving to a goal. The robot is free to move along whichever task path it chooses.  
    We highlight the work by showing fast results in simulated environments with moving obstacles.

Paper
Lazy Reconfiguration Forest (LRF): An Approach for Motion Planning with Mulitple Tasks in Dynamic Environments
Russell Gayle, Kristopher R. Klingler, Patrick G. Xavier
Proceedings of the International Conference on Robotics and Automation (ICRA), 2007
pdf (559K)


Additional Media
Point Robot in the LRF environment with 15 obstacles - (avi) 10MB
Arrow-shaped Robot (3-DoF) with a narrow passage and 2 obstacles - (avi) 20MB
Related Links
Acknowldgements
This work was supported in part by a Department of Energy High-Performance Computer Science Fellowship administered by the Krell Institute, the United States Department of Energy under Contract DE-ACO4-94AL85000. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy.

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