Anytime Safe Interval Path Planning for dynamic environments

Path planning in dynamic environments is significantly more difficult than navigation in static spaces due to the increased dimensionality of the problem, as well as the importance of returning good paths under time constraints. Anytime planners are ideal for these types of problems as they find an initial solution quickly and then improve it as time allows. In this paper, we develop an anytime planner that builds off of Safe Interval Path Planning (SIPP), which is a fast A*-variant for planning in dynamic environments that uses intervals instead of timesteps to represent the time dimension of the problem. In addition, we introduce an optional time-horizon after which the planner drops time as a dimension. On the theoretical side, we show that in the absence of time-horizon our planner can provide guarantees on completeness as well as bounds on the sub-optimality of the solution with respect to the original space-time graph. We also provide simulation experiments for planning for a UAV among 50 dynamic obstacles, where we can provide safe paths for the next 15 seconds of execution within 0.05 seconds. Our results provide a strong evidence for our planner working under real-time constraints.

[1]  Wolfram Burgard,et al.  The dynamic window approach to collision avoidance , 1997, IEEE Robotics Autom. Mag..

[2]  Jean-Claude Latombe,et al.  Randomized Kinodynamic Motion Planning with Moving Obstacles , 2002, Int. J. Robotics Res..

[3]  Sebastian Thrun,et al.  ARA*: Anytime A* with Provable Bounds on Sub-Optimality , 2003, NIPS.

[4]  Thierry Fraichard,et al.  Safe motion planning in dynamic environments , 2005, 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[5]  Alonzo Kelly,et al.  Generating near minimal spanning control sets for constrained motion planning in discrete state spaces , 2005, 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[6]  Mark H. Overmars,et al.  Roadmap-based motion planning in dynamic environments , 2004, IEEE Transactions on Robotics.

[7]  Mark H. Overmars,et al.  Roadmap-based motion planning in dynamic environments , 2005, IEEE Trans. Robotics.

[8]  Jur P. van den Berg,et al.  Anytime path planning and replanning in dynamic environments , 2006, Proceedings 2006 IEEE International Conference on Robotics and Automation, 2006. ICRA 2006..

[9]  Kostas E. Bekris,et al.  Greedy but Safe Replanning under Kinodynamic Constraints , 2007, Proceedings 2007 IEEE International Conference on Robotics and Automation.

[10]  Maxim Likhachev,et al.  Time-bounded lattice for efficient planning in dynamic environments , 2009, 2009 IEEE International Conference on Robotics and Automation.

[11]  Maxim Likhachev,et al.  Planning Long Dynamically Feasible Maneuvers for Autonomous Vehicles , 2008, Int. J. Robotics Res..

[12]  Dinesh Manocha,et al.  Generalized velocity obstacles , 2009, 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[13]  Roland Siegwart,et al.  Smooth path planning in constrained environments , 2009, 2009 IEEE International Conference on Robotics and Automation.

[14]  Emilio Frazzoli,et al.  Incremental Sampling-based Algorithms for Optimal Motion Planning , 2010, Robotics: Science and Systems.

[15]  Maxim Likhachev,et al.  Planning in Domains with Cost Function Dependent Actions , 2011, SOCS.

[16]  Maxim Likhachev,et al.  SIPP: Safe interval path planning for dynamic environments , 2011, 2011 IEEE International Conference on Robotics and Automation.