Bats are among the most unorthodox fliers of the animal kingdom. Unlike birds, flying mammals can dynamically reshape and modify their wings to achieve maximum strength and hover in place. The soft membrane of their wings, which looks more like a human wing than a bird’s wing, is also extremely flexible, meaning bats can be contoured to squeeze into small corridors.
Now, researchers from Northeastern University are building on those unique elements and applying them to a fully autonomous flying drone called Aerobat. Ultimately, they believe this bat-inspired robot could be used to navigate sewer tunnels, caves and other narrow corridors largely off limits to current flying robots.
Bats are ‘fundamentally different’ fliers
The researchers, who published their findings in International Journal of Robotics Research Late last month, it used a combination of hard and soft 3D-printed materials to form the base of the Aerobat’s wings. Like its real-life doppelganger, Aerobat’s thin, flexible arms expand on downstrokes and collapse on upstrokes. This motion, according to the paper, creates “periodic air planes” that are used to maximize net positive aerodynamic force. The result is a very efficient method of maintaining flight.
“Some literature refers to bat flight as dancing in the air,” Northeastern professor of electrical and computer engineering and lead author of the paper, Alireza Ramezani, said in a statement. “They don’t just fly, they jump in the air with great coolness. They try to manipulate their fluid environment, and that’s unique to bats.”
In addition to its wings, Aerobat uses a camera to determine its position and orientation. A set of onboard computers are then used for automatic flight control. A human still has to manually set Aerobat’s final destination. However, once this is determined, the robotic bat will flap its arms and navigate to its destination completely autonomously. The aerobot can then hover in place and use an array of sensors to gather data about its environment.
“The whole idea is to design bio-inspired drones that can operate within extremely tight and confined environments,” Ramezani said. Ramezan has spent the past three years studying how bat moments can be incorporated into a flying device. An earlier prototype version of the Aerobat, called “Bat Bot” appeared in a 2017 Nature article.
Modern robots take inspiration from living creatures
Scientists are no strangers to drawing on nature for inspiration. Previous bird-inspired quadcopters have used hawk-like talons and toe pads to grip ledges and land smoothly just about anywhere. Other researchers have already developed robots based on daddy longlegs spiders, cockroaches, dogs and long-extinct sea creatures, just to name a few. In each of these cases, the natural elegance of biology’s movement and function is helping researchers solve real-world problems.
For Aerobat, that could mean one day being used to collect data from sewer systems or other hard-to-reach infrastructure areas. The researchers say their robot could also be equipped with a depth-sensing camera for monitoring the environment. If successful, Aerobat will join a growing list of new robots used to monitor nuclear facilities and other dangerous areas largely inaccessible to humans.
“The issue is that we are surrounded by limited environments and we don’t have fast robots that can help us with remote sensing and other applications,” Ramezani said.