Real-life hummingbirds have taught a tiny winged robot how to hover, fly sideways and all the other tricks that no other bird in nature can do.

The hummingbird drone is being developed as a rescue probe that can locate people trapped in collapsed buildings – or hiding in cluttered spaces.

For all its cuteness, the hummingbird, which is completely silent, could be a devastating tool in covert operations – even assassinations.

The 12-gram hummingbird has a 3D-printed body, wings made of carbon fibre and laser-cut membranes and is able to behave independently because of AI capabilities and learning.

It appears to solve a problem that can’t be met by ordinary quad-copter drones – the aerodynamic limitations of smallness. A bug-sized quad-copter wouldn’t be able to generate enough lift to support its weight.

No limitations on size

Hummingbirds – and insects – don’t use conventional aerodynamics, and their wings are both resilient and astonishingly flexible.

“The physics is simply different; the aerodynamics is inherently unsteady, with high angles of attack and high lift,” said project leader Xinyan Deng, an associate professor of mechanical engineering at Purdue University in Indiana, in a prepared statement.

“This makes it possible for smaller, flying animals to exist, and also possible for us to scale down flapping wing robots.”

Military organisations see the potential

For years the US military has been trying to crack the hummingbird code, to access tiny and hard-to-reach spaces, presumably with elusive terror targets in mind.

In 2011, AeroVironment built a robotic hummingbird for the US Defence Advanced Research Projects Agency that was heavier than a real one – and not as fast. It had helicopter-like flight controls, limited manoeuvrability and it required a human to be behind a remote control at all times.

Dr Deng’s group and her collaborators went back to the drawing board, so to speak, studying hummingbirds in the wild over multiple summers in Montana.

According to the university’s statement, they documented key hummingbird manoeuvres, such as making a rapid 180-degree turn, and translated them to computer algorithms the robot could learn from when hooked up to a simulation.

This means, after learning from a simulation, the robot knows how to move around on its own like a real hummingbird would, “such as discerning when to perform an escape manoeuvre”.

Artificial intelligence also allows the robot “to teach itself new tricks”.

Even though the robot doesn’t yet have cameras to see, for example, it senses by touching surfaces. Each touch alters an electrical current, which the researchers realised they could track.

Finds its way in the dark like a bat

“The robot can essentially create a map without seeing its surroundings,” Dr Deng said, an associate professor of mechanical engineering at Purdue.

“This could be helpful in a situation when the robot might be searching for victims in a dark place — and it means one less sensor to add when we do give the robot the ability to see.”

Further study on the physics of insects and hummingbirds allowed Purdue researchers to build robots smaller than hummingbirds (and even as small as insects) without compromising the way they fly.

“The smaller the size, the greater the wing-flapping frequency, and the more efficiently they fly,” Dr Deng said.

The researchers will present their work on May 20 at the 2019 IEEE International Conference on Robotics and Automation in Montreal.

Their three papers leading to the actual robot can be found here, here, and here.