Path Planning for Mobile Robots Wavefront Dependency Tracking Interweaving Mapping, Planning, and Control Dependency Tracking for Fast Marching — Dynamic Replanning for Ground Vehicles Roland Philippsen Robotics and AI Lab, Stanford, USA Fast Marching Method Tutorial, IROS 2008 Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Overview Wavefront Dependency Tracking Path Planning Approaches Interweaving Mapping, Planning, and Control Costmap Planning with E ∗ Motivation Mobile Tour-Guides Autonomous Cars example: Robox, Expo.02 example: SmartTer, Elrob 2006 Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Overview Wavefront Dependency Tracking Path Planning Approaches Interweaving Mapping, Planning, and Control Costmap Planning with E ∗ Talk Outline 1 Path Planning for Mobile Robots 2 Wavefront Dependency Tracking 3 Interweaving Mapping, Planning, and Control Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Overview Wavefront Dependency Tracking Path Planning Approaches Interweaving Mapping, Planning, and Control Costmap Planning with E ∗ Classes of Path Planning Approaches road maps : extract network then search graph cell decomposition : compute sub-regions then search graph potential fields : attraction to goal, repulsion from obstacles navigation functions : potentials without local minima randomized search: approximate rapid roadmaps Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Overview Wavefront Dependency Tracking Path Planning Approaches Interweaving Mapping, Planning, and Control Costmap Planning with E ∗ Overview of Costmap Planning but avoid this: general idea steps incur cost such as energy use or collision risk paths accumulate cost find the optimum path the approach of E ∗ cost attached to nodes (as opposed to edges ) graph semantics, user-defined interpolation usually though: 1 st order upwind propagation on a grid Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Overview Wavefront Dependency Tracking Path Planning Approaches Interweaving Mapping, Planning, and Control Costmap Planning with E ∗ E ∗ in Context (Related Approaches) user configurable E ∗ [Philippsen, 2004] information reuse D ∗ [Stentz, 1995] multi-resolution Field-D ∗ [Fergusson, 2006] Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Wavefronts for Navigation Wavefront Dependency Tracking Cost Maps as Speed Maps Interweaving Mapping, Planning, and Control Dependency Tracking for Replanning Navigation Functions from Wavefront Propagation variable speed propagation speed depends only on position ⇒ Fast Marching Method! crossing-time Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Wavefronts for Navigation Wavefront Dependency Tracking Cost Maps as Speed Maps Interweaving Mapping, Planning, and Control Dependency Tracking for Replanning Using the Level Set Method for Interpolation � = but ≡ Γ( t ) : closed ( N − 1)D surface R N → R solve ∂ Φ Φ( � x , t ) : ∂ t + F |∇ Φ | = 0 where t 0 : Φ( � x , t = 0) = ± d ( � x , Γ( t = 0)) ⇒ Γ( t ) = { � x | Φ( � x , t ) = 0 } [Sethian, 1996] Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Wavefronts for Navigation Wavefront Dependency Tracking Cost Maps as Speed Maps Interweaving Mapping, Planning, and Control Dependency Tracking for Replanning Cost Maps as Speed Maps costmap ≡ propagation speed � ∂ Φ obstacle: F = 0 ∂ t + F |∇ Φ | = 0 free: F = 1 example with C projection Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Wavefronts for Navigation Wavefront Dependency Tracking Cost Maps as Speed Maps Interweaving Mapping, Planning, and Control Dependency Tracking for Replanning Dependency Tracking for Replanning upwind tracking cost increase (speed decrease): re-propagate to downwind neighbors cost decrease: re-propagate to all neighbors Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Navigational Components Wavefront Dependency Tracking Planning, Mapping, Control on Growable Costmaps Interweaving Mapping, Planning, and Control Conclusion and Outlook Scopes of Space and Time information transitions local ↔ global W ↔ C realtime ↔ non-RT Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Navigational Components Wavefront Dependency Tracking Planning, Mapping, Control on Growable Costmaps Interweaving Mapping, Planning, and Control Conclusion and Outlook Requirements for Wheeled Robots integrate planning with (at least) mapping and control building a costmap W or C ? projected C ? representation — grid, graph, multiresolution? bounds? — grow on demand map changes during lifetime exploration changing environment change in localization controllers require smooth and “always available” paths overall responsiveness, reuse information Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Navigational Components Wavefront Dependency Tracking Planning, Mapping, Control on Growable Costmaps Interweaving Mapping, Planning, and Control Conclusion and Outlook Example: Robox, Expo.02 Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Navigational Components Wavefront Dependency Tracking Planning, Mapping, Control on Growable Costmaps Interweaving Mapping, Planning, and Control Conclusion and Outlook Growable E ∗ System Architecture separate the costmap from the planning space cost modification buffer possibly different domain descriptions well-defined places for preferences and heuristics manage shared access to costmap navigation function planned path Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Navigational Components Wavefront Dependency Tracking Planning, Mapping, Control on Growable Costmaps Interweaving Mapping, Planning, and Control Conclusion and Outlook Illustration diff drive scenario autonomous car scenario Roland Philippsen Replanning for FFM — IROS 2008
Path Planning for Mobile Robots Navigational Components Wavefront Dependency Tracking Planning, Mapping, Control on Growable Costmaps Interweaving Mapping, Planning, and Control Conclusion and Outlook Conclusion and Outlook pushing the E ∗ concept. . . costmap planning allows to generlized interpolation concisely express complex kernel? optimization criteria kinodynamic planning handle non-binary and non-uniforms grids, incomplete world models lattices, triangulated integrating replanning means surfaces. . . addressing multiple replanning for general scopes of information case LSM? buffering changes to the world model http://estar.sourceforge.net/ Roland Philippsen Replanning for FFM — IROS 2008
Recommend
More recommend
