CFD-based Underwater Formation Analysis for Multiple Amphibious Spherical Robots

As limited sensing and working capability of a single robot, multiple robots cooperative accomplishing complex tasks in formation has been a popular topic in recent years. Energy efficiency is the premise and guarantee for underwater robot to complete a wide range of task, especially for the small and bionic amphibious spherical robots with limited energy. This paper analyzed three formation shapes in the view of underwater hydrodynamic drag aiming at decreasing the energy consumption of a multiple robots system. Numerical simulation based on Computational Fluid Dynamic (CFD) is adopted to compute the drag of each individual robot and entire systems. Simulation results show that triangular formation shape can decrease the total drag. When the serial and parallel formation are needed, the longitudinal distance and transverse distance should be short as soon as possible.