Integrated Planning and Execution: Elastic Strips

Real-time replanning is a prerequisite for motion execution in unpredictably changing environments. This paper presents a framework that allows real-time replanning in high-dimensional configuration spaces. Initially, a planning operation generates a path. The path is augmented by a set of paths homotopic to it. This set is represented implicitly by a volume of free space in the workspace. Effectively, this corresponds to delaying part of the planning operation until motion execution. During execution, reactive control algorithms select a valid path from the set of homotopic paths, using proximity to the environment as a simple and effective heuristic and thereby significantly pruning the search in the configuration space. Experimental results are presented to validate the real-time performance of this framework in high-dimensional configuration spaces.