Natural decomposition of free space for path planning

This paper describes an algorithm that decomposes the free space into nonoverlapping geometric-shaped primitives suitable for path planning. Given a set of polygonal obstacles in space, the algorithm first decomposes concave obstacles into connecting convex obstacles in order to have a uniform obstacle representation, which facilitates later processing. The neighborhood relations among these Convex obstacles are identified and then used to locate critical "channels" and "passage regions" in the free space, and to localize the influence of obstacles on free space description. The free space is then decomposed into nonoverlapping geometric-shaped primitives where channels connect passage regions. The channels are similar to the generalized cones presented in Brooks [1]. The passage regions are represented as convex polygons. Based on this mixed representation of free space, the path planning algorithm can plan path trajectories inside the channels and passage regions. The perimeter of the channels and passage regions associated with the planned path provides the boundaries of the path that the mobile robot must stay within during path execution.