Borrowing design ideas from the natural world, researchers at Stanford University have created a new type of drone that can overcome the limitations of its maximum thrust and reel in payloads 40 times as heavy as itself.
This class of drones has been named ‘FlyCroTugs’ and a single drone weighs a mere 100 grams. They employ controllable adhesion combined with wasp-inspired tiny metal hooks called microspines to cling to the ground and then employ a powerful tether to pull an object towards themselves. This sequence of movements allows the FlyCroTug to transport objects that would have been too heavy to move while flying.
Wasps generally use their stingers to subdue their prey, before transporting it back to their nest. However, some types of wasps which hunt prey bigger than themselves, such as tarantula hawk wasps, use microspines to plant their feet into the ground and drag their prey home. Often, tarantula hawk wasps’ prey is eight times as heavy as them.
Forceful manipulation such as pulling and pushing has generally been the domain of large, mobile, terrestrial robots thus far. However, their size and weight restricts them to two-dimensional movement on unobstructed flat surfaces. In comparison, Micro Air Vehicles have had their roles limited to the gathering of data and surveillance without physical interaction with the environment. The development of the FlyCroTug could be the first step to changing this status quo.
However, there are some limitations to the robots’ current design. Because of limited battery size, the FlyCroTug only has a fly-time of five minutes. This means they are limited to short range operations, and that the more complex a task, the more drones will be needed.