Water Surface Stability Prediction of Amphibious Bio-Inspired Undulatory Fin Robot

To solve the interference problems of wind and wave action and load movement when switching under water surface conditions in the marine environment, a study on the water surface stability prediction of the bio-inspired undulatory fin robot is carried out. Based on the fin motion equation and fluid drag theory, a water surface stability calculation model of the robot is established. The study compares the effects of different loads and heel angles on the stability of the robot's water surface under different calculation methods and verifies the validity of the model through computational fluid dynamics methods. The simulation results show that the water surface stability of the robot exhibits sinusoidal-like changes over time, which is equal to the undulatory fin period. The stability decreases with the increase of the drainage volume. When the drainage volume is constant, the stability first increases and then decreases with the increase in heel angle. The theoretical calculation results are consistent with the numerical results, which verify the effectiveness of the water surface stability prediction model proposed in this paper. It can provide a theoretical basis for the optimization design of water surface stability of the undulatory fin robot.