Distributed Traversability Analysis of Flow Field Under Communication Constraints

Traversability analysis, previously developed for ground robots, is extended to be performed by a group of marine vehicles over ocean flow fields. To enable distributed path planning against flow, a systematic method is developed to determine a flow map that is significant for sharing among vehicles. Using traversability analysis, each vehicle finds a set of support vectors to approximate the boundary of flow regions with strong average flow speed. These support vectors, together with the parameters determined by the traversability analysis, are then shared over the communication links. The shared information is used by each vehicle to construct a flow map that supports path planning algorithms running on each vehicle. Underwater communication limits the amount of information contained in a map that can be shared among vehicles. A novel method for information reduction is developed so that only reduced flow maps are shared. The length of the data packets can be adjusted through an optimization process that balance between the fidelity of the approximated boundary and the number of bits that need to be transmitted. Simulation results demonstrate that the flow maps constructed from the shared information can have sufficient quality to allow near-optimal paths to be generated.