Real-time Motion Planning in Changing Environments Using Topology-based Encoding of Past Knowledge

Trajectory planning and replanning in complex environments often reuses very little information from the previous solutions. This is particularly evident when the motion is repeated multiple times with only a limited amount of variation between each run. To address this issue, we propose the DRMconnect algorithm, a combination of dynamic reachability maps (DRM) with lazy collision checking and a fallback strategy based on the RRT-connect algorithm which is used to repair the roadmap through further exploration. This fallback allows us to use much sparser roadmaps. Furthermore, we investigate using an approximate Reeb graph to capture the topologypersistent features of the past solutions of the problem utilising this sparsity. We evaluate DRM-connect with a Reeb graph on reaching tasks, and we compare it to state-of-the-art methods. We show that the proposed method outperforms both RRTconnect and BKPIECE algorithms in the number of collision checks required and we show that our method has the potential to scale to systems with higher number degrees of freedom.