A seed-inspired monocopter thought takes flight

From a seed-inspired design to a 26-minute flight time on a single rotor, a brand new monocopter developed by SUTD researchers marks a 10-year journey in direction of redefining how environment friendly small flying robots will be.

When Singapore celebrated its fiftieth yr of independence in 2015, a staff of scholar researchers led by Affiliate Professor Foong Shaohui from Singapore College Expertise and Design (SUTD) launched into an formidable problem: to design and construct a drone able to 50 minutes of sustained flight.

On the time, most hobbyist quadcopters might barely handle half of that. The SG50 Multi-Rotor Drone mission succeeded, however to fly that lengthy, the craft needed to be giant, advanced, and heavy.

A decade on, Assoc Prof Foong has reached new heights in his drone analysis—this time by going small and pursuing a very completely different technique. Fairly than attempting to engineer the multi-rotor drone to be extra environment friendly, which is inherently inefficient by design, he turned to nature for inspiration and developed a samara-inspired light-weight monocopter that achieves environment friendly and totally controllable flight with solely a single actuator.

In a research printed in IEEE Robotics and Automation Letters titled “Design and Optimization of a Samara-Impressed Light-weight Monocopter for Prolonged Endurance,” he embraced autorotation and leveraged aerodynamic effectivity over brute-force thrust and demonstrated a minimalist but extremely environment friendly design: a 32-gram, light-weight monocopter that may hover with full automated management for 26 minutes, far surpassing typical drones in its class.

It’s a part of a broader effort, stated Assoc Prof Foong, to show the design of flying robots on its head, by doing extra with much less. His new design broke new floor for rotorcraft on this weight class.

“Attaining flight turns into more and more inefficient as you scale down. Small drones typically have poor endurance as a result of their small propellers generate restricted thrust and but nonetheless draw vital energy. Our objective was to beat that constraint,” he added.

The answer, because it seems, was to look to nature. Samaras, spinning maple seeds that spiral gently to the bottom, supply a compelling aerodynamic mode, combining passive stability with environment friendly carry technology in a superbly easy type.

“Each a part of a maple seed contributes to carry. We took inspiration from that precept and constructed an airframe the place nothing is wasted,” Assoc Prof Foong defined.

The technique of utilizing samara seeds as inspiration stemmed from a human-centered statement—one thing AI wouldn’t have recognized by itself. The improved wing design was then achieved by AI-powered optimization, which enabled the staff to effectively discover design prospects with out exhaustively testing each configuration.

In distinction to traditional quadcopters that management a number of rotors, the staff’s monocopter achieves flight with only one actuator. This single motor drives a winged physique right into a spin, stabilizing it by passive dynamics whereas offering carry by a big airfoil. With out flapping elements, gearboxes or mechanical linkages, the design is structurally easy and but mechanically environment friendly.

Behind the monocopter’s success is an intensive design optimization course of, which mixes classical aerodynamic idea with real-world efficiency modeling. The SUTD researchers used a surrogate optimization methodology, a type of data-driven search algorithm, to fine-tune the wing form, pitching angle, and mass distribution.

The ensuing drone hovers with an influence loading of 9.1 grams per watt, outperforming different hovering-capable micro air autos of comparable measurement and weight.

“It is a first-of-its-kind achievement,” Analysis Fellow Cai Xinyu famous. “We have demonstrated that with the proper aerodynamic and system-level design, a tiny aerial robotic can obtain endurance that rivals a lot bigger techniques. This exhibits that measurement now not must be a limiting issue.”

The monocopter’s endurance and ease are a boon for low-cost, long-duration missions. Among the many purposes being explored is a light-weight, reusable radiosonde, a balloon-borne instrument for climate sensing and monitoring, which was the Sustainability Winner at The James Dyson Award 2024.

Whereas the present prototype makes use of commercially accessible elements, future work will look into creating bespoke elements to push efficiency additional.

“The following step is to extend payload capability and flight time with out considerably growing weight,” shared Xinyu. “We’re additionally trying to discover superior supplies and bio-inspired wing morphologies into the design course of.”

The story of the staff’s monocopter can be one in all continuity. The most recent breakthrough marks a 10-year evolution because the SG50 endurance problem, and the staff has set its sights on a symbolic follow-up: a monocopter able to flying greater than 60 minutes for Singapore’s sixtieth birthday.

In comparison with the big SG50 quadcopter, the SG60 monocopter is superior in all quantifiable metrics. It’s smaller, less complicated, and greater than twice as power-efficient.

“Effectivity often improves with a rise in scale. Right here, we have reversed that. We have managed to shrink the system whereas making it carry out extra effectively,” added Assoc Prof Foong.

The monocopter mission is an ideal instance of how rigorous engineering and considerate design pondering can flip a nature-inspired thought right into a viable expertise platform.

“It is about understanding the underlying physics, modeling it faithfully, and utilizing that data to push the bounds of what small aerial robots can do,” mirrored Assoc Prof Foong. That features making use of Design AI—combining human-centered design with the facility of AI—a rising a part of how SUTD groups create and refine future-ready options.

“With additional improvement, we see this expertise taking part in a key function in a wide range of established and rising purposes. The sky is really the restrict.”