Birds are technological marvels whose feats science has always tried to emulate. Latest proposal: a raptor drone with more lifelike greenhouses.
Aerial photography, delivery, cartography, scientific analyzes… today, drones are capable of accomplishing a whole range of diverse and varied tasks. But have you ever seen one land and grab objects with talons, like a real raptor?
To make their machines more efficient and solve specific problems, engineers often draw inspiration from the animal kingdom. Drones are no exception; recently, for example, the US military presented a tiny drone inspired by dragonflies. In work recently published in Science and spotted by Interesting Engineering, American researchers at Stanford University attempted to do the same thing, but with uperegrine falcon : here is the Stereotyped Nature-Inspired Aerial Grasper, or SNAG.
Among all the models from which the researchers could have drawn inspiration, this one was certainly not chosen at random. Indeed, this majestic bird has a sacred reputation. It is quite simply the fastest animal on Earth, all categories combined. It is capable of approaching 400 km / h in a dive, which leaves little chance for its prey.
Raptors, engineering marvels
But when you approach almost a third of the speed of sound, it is better to react with a quarter-turn; no question of hesitating when landing or catching prey. It is this extreme precision that interests Stanford engineers. Because despite the clear progress at this level, drones are still relatively clumsy. Like helicopters, they must land in a very controlled manner. It is the reverse of birds, which can land in balance while absorbing an impact.
“For birds, everything looks like an airstrip”, Explains engineer D. Lentik. “It is a real source of inspiration. The idea is that if we imagined a new landing system, we could allow drones to perch anywhere.”, He enthuses. And to imagine this new system, they simply tried to imitate a tool that has been proven for thousands of years in raptors: greenhouses.
But it’s easier said than done. “After millions of years of evolution, birds give us the illusion that catching, taking off and landing is trivial, even in an environment as variable and complex as a forest.”, Tempers his colleague William Roderick.
A mechanical greenhouse larger than life
After months of effort, Stanford engineers finally succeeded in producing a robotic “paw” that mimics that of the peregrine falcon. Like its biological equivalent, it is subdivided into several segments which act as muscles. In parallel, a set of cables, pulleys, motors and springs play the role of tendons. This structure allows the “talons” to instantly close around the target – a perch or prey – while absorbing the impact in what the researchers describe as a “dynamic collision”.
Once the embrace is tightened, the motors at the base of the bionic limb – where the animal’s hip would normally be – allow it to stabilize quietly on its new perch, or above its prey.
According to its designers, the system works remarkably well. The drone was shown to be able to land on heaps of branches of very different shapes. He even managed to do it on slippery surfaces. The icing on the cake: like a real tame raptor, SNAG even managed to catch objects thrown by researchers on the fly!
It is above all an experimental system; As it stands, the team has no plans to market a domestic robot hawk. But it is not a gadget devoid of interest. Because allowing drones to “rest” in this way on previously inaccessible surfaces could open the doors to environments that were once very inhospitable to them, such as tropical forests. They could thus become a platform of choice for monitor biodiversity or climatic conditions in these ecosystems.
Ultimately, these drones could get even closer to real raptors. Researchers are even imagining other functions that could become reality once this technology matures; these mechanical hawks could for example make the bird hunting at airports, where they represent a real logistical headache on a daily basis. The text of the study is available here.