| Biomimetic underwater robots have become a research hotspot in the field of underwater equipment due to their excellent mobility and environmental adaptability. Some models adopt a dorsal fin oscillation mechanism to achieve depth regulation. However, during the oscillation of the dorsal fin, periodic interaction forces are generated between the fin surface and the water body, which in turn cause the roll and sway of the vehicle body, leading to a decrease in the accuracy of internal sensors and an increase in additional energy consumption. To address this problem, this study proposes an anti-rolling stabilization strategy based on the oscillation of double dorsal fins with a 180° phase difference. Firstly, based on the dynamic mechanism of single dorsal fin oscillation, the transmission process of the finwater interaction torque is derived, and the inherent cause of the roll phenomenon is clarified. Secondly, a double dorsal fin structure symmetric about the midplane of the vehicle is designed, and the symmetric oscillation of the double dorsal fins is used to realize the mutual cancellation of the interaction torques in the horizontal direction. Finally, a Computational Fluid Dynamics (CFD) simulation model of this anti-rolling structure is established, and simulation analyses are carried out for five typical working conditions: single dorsal fin oscillation, in-line and same-direction oscillation of double dorsal fins, in-line and opposite-direction oscillation of double dorsal fins, sideby-side and same-direction oscillation of double dorsal fins, and side-by-side and opposite-direction oscillation of double dorsal fins. The results show that under the working condition of side-by-side and opposite-direction oscillation of double dorsal fins, both the maximum roll angle and the maximum sway displacement of the vehicle are significantly reduced, and the average vertical thrust reaches more than 1.9 times that of the single dorsal fin oscillation condition, which can effectively meet the demand for depth regulation. This study provides a new technical scheme and theoretical support for solving the stability problem of bionic underwater vehicles caused by dorsal fin oscillation. |
