Micro-drones are nifty little things: small, fast, and agile. But they’re not the strongest machines around, and are barely capable of exerting more force than a small mouse head-butting your ankle. Until now. Scientists from Stanford University and EPFL in Switzerland have created a micro-drone with a built-in winch that’s capable of lifting up to 40 times its own weight and performing simple mechanical tasks like opening a door.
The key to the design is the use of interchangeable adhesives on the drone’s base: microspines for digging into rough materials like stucco, carpet, or rubble, and ridged silicone (inspired by the morphology of gecko feet) for grabbing onto glass. Both microspines and silicone ridges only cling to surfaces in one direction, meaning they can be easily detached. With these in place, the micro-drones can pull well above their 100-gram weight, exerting 40 newtons of force or enough to lift four kilograms (about eight pounds).
The drone’s design was inspired by wasps
The design was inspired by nature, says Matthew Estrada, a PhD candidate at Stanford’s Biomimetics and Dexterous Manipulation Lab and co-author on the paper. The team looked to small flying insects as the nearest equivalent to micro-drones, and studied how wasps particularly are able to move prey much heavier than themselves.
“Wasps quite often will want to grab large prey and move it back to their den,” Estrada told The Verge. But, if they don’t have enough muscle power to fly with their cargo “they have to drag it along the ground, hooking on with their claws and moving it bit by bit.” These winch-equipped micro-drones — named FlyCroTugs — work exactly the same way.
What can you actually do with a machine like this, though? Well, opening doors is one thing, although Estrada notes that when the team tried this out it was a difficult process. They had to build a hook that fit the door handle, and lining up the drones correctly took minutes of careful maneuvering. “It was challenging in that a number of things had to go right,” says Estrada.
But, this is just a proof of concept, and the basic idea that we can create micro-drones that don’t just fly around spaces but also manipulate them is enticing. Squads of cheap, disposable micro-drones could work together in the future, clearing rubble for larger robots in disaster scenarios for example.
“More generally, if you look at most small flying things, they’re interacting with their environments through the use of these mechanisms all the time: they’re perching, climbing, dragging things along,” says Estrada. Micro-drones are now learning the same skills.