Hierarchical Elastic Formation Control for Multiple Autonomous Surface Vessels

This paper introduces a hierarchical elastic formation control approach for multiple autonomous surface vessels (ASVs) navigating through irregular narrow waterways. Specifically, the high-level elastic formation control strategy is developed to achieve two schemes by using a navigation vector field technique: the coordination of two subgroups of ASVs along sub-channels to merge into a single elastic formation pattern along the main channel, and the splitting of the elastic formation pattern into two subgroups to facilitate obstacle avoidance. The low-level individual regulator is presented for ASV to track the virtual control velocity. Sufficient conditions are derived for the input-to-state stability of the closed-loop multi-ASV systems. Numerical simulations are elaborated to empirically validate the effectiveness of the elastic formation control method.