Skip to content
University of Maryland LibrariesDigital Repository at the University of Maryland
    • Login
    View Item 
    •   DRUM
    • College of Computer, Mathematical & Natural Sciences
    • Computer Science
    • Technical Reports of the Computer Science Department
    • View Item
    •   DRUM
    • College of Computer, Mathematical & Natural Sciences
    • Computer Science
    • Technical Reports of the Computer Science Department
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Guaranteeing Safety in the Presence of Moving Obstacles

    Thumbnail
    View/Open
    CS-TR-3984.ps (5.580Mb)
    No. of downloads: 157

    Date
    1999-01-20
    Author
    Kohout, Robert
    Metadata
    Show full item record
    Abstract
    Path planning is a fundamental problem in robotics research. Whether the robot is a manipulator arm in a factory floor, an unmanned all-terrain vehicle, a flying drone, or a household assistant serving coffee, the motions of the robot must be planned and executed in such a way that the robot can accomplish its goals. Motion planning must take into account the robot's inherent abilities to move and maneuver, its speed, and all of the various constraints imposed upon these abilities by the environment in which the robot is situated. Many real-world application domains are dynamic, in the sense that the plan-relevant parameters in the environment evolve over time. In such cases, motion planning must also take into account the time that it takes to plan. A perfect plan is useless if it cannot be produced in time to execute it in a changing world. This technical report focuses upon the problem of avoiding moving obstacles in a 2-dimensional environment. Specifically, it addresses the problem of guaranteeing that a robot will never be hit by an obstacle in the environment. It establishes conditions for guaranteeing that a safety-preserving path will always exist in the most commonly studied problem in moving obstacle avoidance, known as the Asteroids Avoidance Problem. These results are then extended to less restricted, more realistic variants of the problem, including the important case where the locations and trajectories are only made known to the planning algorithm at runtime. Once these conditions are established, they are used to develop an incremental algorithm that can solve the restricted Asteroids problem in low-order polynomial time. This algorithm takes its own observed worst-case running time into account, completes in a fraction of a second, and has been used to control Dodger, a simulated robot that avoids moving obstacles in hard real time. In over ten machine-weeks of testing, involving well over a million obstacles generated in a variety of ways, Dodger has not been hit by a single obstacle. (Also cross-referenced as UMIACS-TR 99-06)
    URI
    http://hdl.handle.net/1903/504
    Collections
    • Technical Reports of the Computer Science Department

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility
     

     

    Browse

    All of DRUMCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister
    Pages
    About DRUMAbout Download Statistics

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility