A Flexible Hingeless Control Surface Inspired by Aquatic Animals

A flexible hingeless control surface model was proposed for motion control of Underwater Vehicles (UVs), which is inspired by the flexible bending control surfaces of underwater creatures, such as fish and squid. Computational Fluid Dynamics (CFD) simulation demonstrates that, in comparison with the hinged or rigid control surface, the proposed flexible bending control surface can suppress the flow separation so as to improve the turning performance. A prototype of the flexible control surface was fabricated, in which Shape Memory Alloy (SMA) wires were selected as the actuators. The elastic energy storage and exchange mechanism was incorporated into the actuation of the control surface to improve the efficiency. Thermal analysis of SMA wires was performed to find proper actuating condition. Open-loop bending experiments were carried out. The results show that the proposed control surface can achieve the maximum bending angle of 104°. Moreover, the power and energy consumption under different pulse conditions were compared.