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Paper details
Number 2 - June 2017
Volume 27 - 2017
D* Extra Lite: A dynamic A* with search-tree cutting and frontier-gap repairing
Maciej Przybylski, Barbara Putz
Abstract
Searching for the shortest-path in an unknown or changeable environment is a common problem in robotics and video
games, in which agents need to update maps and to perform re-planning in order to complete their missions. D* Lite is
a popular incremental heuristic search algorithm (i.e., it utilizes knowledge from previous searches). Its efficiency lies in
the fact that it re-expands only those parts of the search-space that are relevant to registered changes and the current state
of the agent. In this paper, we propose a new D* Extra Lite algorithm that is close to a regular A*, with reinitialization
of the affected search-space achieved by search-tree branch cutting. The provided worst-case complexity analysis strongly
suggests that D* Extra Lite’s method of reinitialization is faster than the focused approach to reinitialization used in D*
Lite. In comprehensive tests on a large number of typical two-dimensional path-planning problems, D* Extra Lite was 1.08
to 1.94 times faster than the optimized version of D* Lite. Moreover, while demonstrating that it can be particularly suitable
for difficult, dynamic problems, as the problem-complexity increased, D* Extra Lite’s performance further surpassed that
of D*Lite. The source code of the algorithm is available on the open-source basis.
Keywords
shortest-path planning, incremental heuristic search, mobile robot navigation, video games