Drones are often considered to be mechanical versions of birds. In fact, drone designers often study real life birds as they seek to equip their drones with a deft maneuverability beyond the capability of helicopters and fixed wing aircraft, So, it’s hardly surprising that a new drone model has just emerged with a distinctly avian ability: Grasp and perching on a tree limb.
The drone, developed by research engineers at Stanford University, has hard plastic grips that closely resemble the claws of a peregrine falcon. The Stanford team came up with the design by studying the movements of small parrots as they flew back and forth between their perches. The researchers placed special sensors on those perches to measure the physical force of landing, perching and takeoff.
“What surprised us was that [the parrots] did the same aerial maneuvers, no matter what surfaces they were landing on,” one of the researchers, William Roderick, explained in a news release. “They let the feet handle the variability and complexity of the surface texture itself,” he said.
The researchers even came up with a clever name for their new drone – a Stereotyped Nature-Inspired Aerial Gripper, or SNAG, for short. Using 3-D imaging, the drone mimics the structure of a falcon’s legs, which are motorized to allow for lateral movement, while a separate motor allows the SNAG’s claws to grasp. SNAG can land on tree limbs, branches and telephone wires – indeed, anywhere a bird might perch. Remotely piloted, it uses its quadcopter rotary power to relaunch itself at will.
SNAG enjoys another operational advantage over less bird-like drones. While perching, it preserves battery power that might otherwise be expended hovering. Given the limited duration of most drone flights SNAG has the potential to keep itself flying for longer, even allowing the craft to recharge without having to return to a docking station.
What kind of tasks can SNAG perform? Just about anything that might require grasping and carrying an object, Roderick says. Right now, SNAG is designed as a relatively light aircraft but the same technology could be attached to a much larger drone frame to support search-and-rescue, fire-fighting and remote delivery operations.
Roderick also envisions SNAG being fitted with additional temperature and humidity sensors to conduct environmental monitoring or even to collect garbage and hazardous waste samples too toxic for on-the-ground human surveyors to handle.
SNAG, which made its first live appearance in late 2021, has already come to the attention of some major funding organizations. And there’s talk of another drone prototype in development at Northwestern University that doesn’t just perch like a bird – it also hangs, upside down, like a bat.