Group Formation of Autonomous Underwater Vehicles That Optimizes Energetic Efficiency in Cruising

When AUVs cruise in group, they interact with each other and their energetic efficiency will be influenced. The hydrodynamic interaction among individuals in an AUV group is complex. This challenging hydrodynamic problem is solved by a hybrid, multi-level numerical approach, which consists of individual- and group-level solutions. In the individual-level simulation, based on commercial software and a turbulence model, a full-scale AUV model with realistic propeller morphology is simulated. The result is then input as source information for the group-level solution based on an analytical potential-flow model. This allows us to investigate equilibrium formations for groups of AUVs and evaluate the perspective of energy consumption through their far-field interference. The optimization results suggest that the average energetic consumption of the group may be minimized when leader and follower AUVs stay in a diagonal pattern (i.e. a follower AUV is laterally behind a leader AUV). The AUVs are required to limit their lateral separation distance to maintain the energy saving effect. Our results reveal that, like animals swimming and flying in groups, Autonomous Underwater Vehicles may also adopt specific group formations to optimize energetic efficiency.