LASTEST NEWS AND ACHIEVEMENTS

HOT Our paper Tombo Propeller: Bioinspired Deformable Structure Toward Collision-Accommodated Control for Drones has been accepted by IEEE Transactions on Robotics. (PDF)

• June 25th, 2021 - Apply for Japan's patent title "Drone and drone controller" adapted to drones equipped with Tombo propellers

• November 12th, 2021 - Introduction and transfer of specialized simulation software for aircraft and propeller from JAXA

• January 14th, 2022 - Collaborative meeting with Futaba for development of Tombo propeller for freight drones

The deformable propeller, which is inspired by structure of a dragonfly wing, can bend, twist and even fold upon collision and resume its original shape soon afterward. The most important part of the novel propeller is bendable segment (as shown in the left picture) mimicking the working principle of dragonfly wing's nodus. See more detail at our publication:

https://ieeexplore.ieee.org/document/9115983

At the prototype stage, rigid parts of the propeller are fabricated by 3D printing technique. All of them, then, are glued by nylon tendons that not only play a role of connectors but also reinforce for the propeller. Silicone is poured in to 3D printing mold to form a complete propeller. Seven steps of the frabrication process for 9 inches propeller is shown in the left picture.

A finger's model, which is made by silicone rubber band Dragon skin 30 reinforced by polyimide ribbons, is subjected to a sudden collision with the deformable propeller is rotated at 3200 rpm (revolutions per minute). Within 0.244 second right after collision, the propeller is able to self-recovery and work normal.

The flight test was performed by a custom-built drone equipped with a Tombo propeller. The pilot experiment revealed, for the first time, successful flight performance of the drone with Tombo propeller in basic hovering tasks. As a result, this demonstrates the introduction of softness into the propeller does not compromise the flight ability of a drone.

Thanks to the self-recovery ability of our deformable propeller, the drone is possible to recover from the collision with a mid-air obstacle. The results showed that with just a minimal intervention of classical control strategy, the drone is able to respond quickly to collisions and do not fall to the ground. This recovery behavior not only reduces the damage risk of the drone itself but also enhances the safety of humans on the ground.

Tombo propeller development team and Japan Aerospace Exploration Agency (JAXA) representative had a presentation about research and development on functional propellers for a new generation of drones reducing noise and hazard. The meeting opened up opportunities for cooperation to develop an investigation on the Tombo propeller by sharing state-of-the-art research facilities.