Lab Papers (GRASP)

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Conference Paper

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A. Nash, S. Koenig and M. Likhachev. Incremental Phi*: Incremental Any-Angle Path Planning on Grids. In Proceedings of the International Joint Conference on Artificial Intelligence (IJCAI), pages (in print), 2009.


We study path planning on grids with blocked and unblocked cells. Any-angle path-planning algorithms find short paths fast because they propagate information along grid edges without constraining the resulting paths to grid edges. Incremental path-planning algorithms solve a series of similar path-planning problems faster than repeated single-shot searches because they reuse information from the previous search to speed up the next one. In this paper, we combine these ideas by making the any-angle path-planning algorithm Basic Theta* incremental. This is non-trivial because Basic Theta* does not fit the standard assumption that the parent of a vertex in the search tree must also be its neighbor. We present Incremental Phi* and show experimentally that it can speed up Basic Theta* by about one order of magnitude for path planning with the freespace assumption.



Date Posted: 01 October 2009