Bird-Like Robotic Claw Lets Drones Perch & Snare Prey

Researchers have developed a bird-like robotic claw and leg assembly that allows drones to land and perch on branches and other surfaces like real birds. According to those same researchers, this breakthrough tech will also facilitate the catching of prey while in flight, much like the predatory avian that inspired the study.


Peregrine falcons are known for their impressive grasp, as well as the ability to perch in a wide range of aerial environments. This ability also allows the animal to scoop up intended prey without ceasing flight. This set of abilities, which are shared by a wide range of birds, has long been a desire of roboticists and drone manufacturers alike. However, the actual leg and claw mechanics behind this perching and grasping were not well understood. 

Now, this gap in knowledge and performance capabilities has led a team of researchers from Stanford University to see if they could build a working leg and claw inspired by that peregrine falcon, with some impressive results.

sci robotics
Image Credit: Sci-robotics



“Birds take off and land on a wide range of complex surfaces,” the study published in the journal Science Robotics states. “In contrast, current robots are limited in their ability to dynamically grasp irregular objects.”

Therefore, the study adds, “we developed a biomimetic robot that can dynamically perch on complex surfaces and grasp irregular objects.”

Dubbed SNAG, for Stereotyped Nature-inspired Aerial Grasper, the press release announcing the new landing system explains that their design “improves upon current aerial robot designs that have limited capabilities when it comes to grasping real-world objects or perching during flight to save energy.”

For instance, SNAG can absorb the impact energy when landing on a branch or other surface, and according to the release, “transform that into ‘squeeze force’ to grasp the branch, while balancing over its center of gravity and gripping irregular surfaces.”

The research team also notes that these same bird-inspired mechanics give their robotic bird claw the ability to catch objects out of thin air. For example, the Stanford team launched a beanbag and a tennis ball at a wall-mounted set of artificial bird-like claws and legs, and the system was able to catch them out of mid-air just like a peregrine falcon snaring its prey mid-flight.



One unexpected finding from the team’s research revealed that there appears to be no difference in perching or prey-grasping ability between the two major claw designs found in birds, offering some versatility in future designs. 

As drones become more and more prevalent, and their uses expanded, the ability to take off and land on pretty much any surface will be a significant upgrade to current systems. For instance, the research release concludes, this “could make it useful as a low-cost sensor for monitoring natural ecosystems.”

In the end, given the increased use of drones by foreign powers and criminal organizations alike, developing a bird-like drone leg and claw that can land anywhere and even grab another drone from the sky may offer the U.S. military a unique advantage over increasingly prevalent adversarial systems. Especially given their plans to “unman” the front lines of battle.

Follow and connect with author Christopher Plain on Twitter: @plain_fiction