TomboPropeller: Bioinspired Deformable Structure Toward Collision-Accommodated Control for Drones

Abstract

There is a growing need for vertical takeoff and landing vehicles, including drones, which are safe to use and can adapt to collisions. The risks of damage by collision, to humans, obstacles in the environment, and drones themselves, are significant. This has prompted a search into nature for a highly resilient structure that can inform a design of propellers to reduce those risks and enhance safety. Inspired by the flexibility and resilience of dragonfly wings, we propose a novel design for a biomimetic drone propeller called Tombo propeller. Here, we report on the design and fabrication process of this biomimetic propeller that can accommodate collisions and recover quickly, while maintaining sufficient thrust force to hover and fly. We describe the development of an aerodynamic model and experiments conducted to investigate performance characteristics for various configurations of the propeller morphology and related properties, such as generated thrust force, thrust force deviation, collision force, recovery time, lift-to-drag ratio, and noise. Finally, we design and showcase a control strategy for a drone equipped with Tombo propellers that collides in midair with an obstacle and recovers from collision continuing flying. The results show that the maximum collision force generated by the proposed Tombo propeller is less than two-thirds that of a traditional rigid propeller, which suggests the concrete possibility to employ deformable propellers for drones flying in a cluttered environment. This research can contribute to the morphological design of flying vehicles for agile and resilient performance.

Risks of Drone Use in Light of Literature Studies

“…The aspects mentioned above have a significant impact on the operational safety of the drone. The increase in safety may also result from changes in the design [ 205 , 206 ], appropriate risk analysis tailored to the purpose of the drone [ 163 , 188 , 189 , 202 , 207 , 208 ], and the detection of unexpected behaviours and abnormal situations during the operation of the drone [ 209 , 210 , 211 , 212 , 213 ]. Just as important as the drone’s flight is its landing.…”

Aerodynamic behavior and acoustic signature of propellers fabricated by additive manufacturing

“…They report that at high exibility, e ciency drops rapidly to around 62% − 73% compared to rigid propellers, with thrust loses caused by deformations that modify the blade's aerodynamic pro le [9]. They also assume that low stiffness may induce larger vibration (thrust deviation), in contrast to a higher stiffness which provides better ying performance [11].…”