Folding components are becoming a hallmark of drones made for pilots on the move. Portability is one thing, but the time needed to unpack the aircraft and set it in flight can be an equally important consideration when it comes to search and rescue operations, an area where drones are showing real potential. By studying the intricate folding patterns of beetle wings, scientists in Switzerland have developed a drone that opens up and takes to the skies in less than a second with a couple of swift movements.
The drone is the handiwork of scientists from Switzerland's National Centre of Competence in Research (NCCR) Robotics and the Laboratory of Intelligent Systems (LIS) at École polytechnique fédérale de Lausanne, who take guidance from the natural world to build advanced robotics systems. LIS' previous work includes a drone that uses its wings to crawl on land like a sea turtle and a grasshopper-inspired robot that can jump 27 times its body size.
For its latest bio-inspired machine, the team set out to develop a search and rescue-oriented drone that could take off from a pilot's hands immediately after being removed from a backpack or pocket. But for this they'd need folding wings with a big size reduction and a single degree of freedom so it could snap into action, criteria that led to the study of beetles.
The researchers went through the process of prototyping, modeling and fine-tuning before they arrived at the final design for their beetle-inspired artificial wings. One of the problems they had to address was finding just the right thickness of material. It needed to be thin enough so that the wings could fold easily, but thick enough to withstand the stresses of flight.
The team solved this by using a pattern of tiles of varying thickness, made up of multi-layered material and joined together at the folds with pre-stretched latex, which the researchers say makes for optimal durability and a smooth unfolding.
The result is a drone that when folded up has only 43 percent of the wingspan and 26 percent of the surface area of when it is in operational mode, where its wings measure 200 x 500 x 16 mm (7.87 x 19 x 0.62 in).
While the pattern is quite complex, the wings have a single degree of freedom and can be unfurled with a single movement. And to set it in flight, the user simply tosses is it in the air. The team has put the drone through its paces in wind tunnel testing, where it's reported to have shown only marginally inferior performance to a similar drone sporting permanently rigid wings.
The team is set to present the drone at next week's International Conference on Intelligent Robots and Systems in Korea, and a paper detailing its research can be read online.
Source: EPFL
