Camber-changing flapping hydrofoils for efficient and environmental-safe water propulsion system

Abstract

This research introduces a novel hydrofoil-based propulsion framework for unmanned aquatic robots, inspired by the undulating locomotion observed in select aquatic species. The proposed system incorporates a camber-modulating mechanism to enhance hydrofoil propulsive force generation and eventually efficiency. Through dynamic simulations, we validate the effectiveness of the camber-adjusting hydrofoil compared to a symmetric counterpart. The results demonstrate a significant improvement in horizontal thrust, emphasizing the potential of the cambering approach to enhance propulsive performance. Additionally, a prototype flipper design is presented, featuring individual control of heave and pitch motions, as well as a camber-adjustment mechanism. The integrated system not only provides efficient water-based propulsion but also offers the capacity for generating vertical forces during take-off maneuvers for seaplanes. The design is tailored to harness wave energy, contributing to the exploration of alternative energy resources. This work advances the understanding of bionic oscillatory principles for aquatic robots and provides a foundation for future developments in environmentally safe and agile underwater exploration.

Figures (5)

• Figure 1: Working principles of the system. (a) Swimming maneuvers in dolphins in water resembling hydrofoil
• Figure 2: The complete temporal cycle of the flipper's heave (in black), pitch (in red), and camber (in light blue). (a) Relative velocities of flow and the influential angles of a hydrofoil cross-section at an instant during the periodic oscillation.
• Figure 3: Lift (red) and drag (black) forces simulation for the downstroke motion (a) intermediate and straight position (b) and upstroke motion (c)
• Figure 4: Vertical and horizontal forces plot in one cycle
• Figure 5: Flipper CAD model (left) and focus on the camber-changing hydrofoil (right)