Numerical investigation and swimming performance evaluation on self-propelled hydrodynamics of hybrid-driven biomimetic robotic fish

Widespread attention has been drawn to the underwater biomimetic robotic fish due to its excellent agility and little environmental disturbance. A hybrid-driven bionic robotic fish outfitted with dual-propeller thrusters is suggested in an effort to enhance the robotic fish’s capacity to adapt to its surroundings and perform better in mobility. The hybrid-driven robotic fish’s self-propelled motion is simulated numerically by CFD, and its hydrodynamic performance is assessed. Its swimming performance under the influence of a single propulsion mode and the coupling of hybrid propulsion modes is methodically examined using a unified kinematic model and various self-propelled motion circumstances. These results demonstrate that the hybrid-driven robotic fish has better speed stability in higher speed swimming conditions and higher energy utilization in maintaining low Re number and high St number swimming conditions. It is also found that the longitudinal hydrodynamic coefficient of the caudal fin increases significantly with the increase of the St number, and the tail can’t provide thrust assistance to the robotic fish when the St number is less than about 0.3. The pertinent findings have some bearing on how the new hybrid-driven robotic fish is designed, modeled, and configured in terms of drive parameters.