Hummingbird robot could help find victims trapped in collapsed buildings

Researchers have recently engineered hummingbird flying robots, trained by machine learning algorithms that could help to manoeuvre better through collapsed buildings and other cluttered spaces to find trapped victims.

Artificial intelligence, combined with flexible flapping wings, allows the robot to teach itself new tricks. Even though the robot can't see yet, for example, it senses by touching surfaces. Each touch alters an electrical current, which the researchers realised they could track.

"The robot can essentially create a map without seeing its surroundings. 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," said one of the researchers Xinyan Deng in the study presented at the meeting of International Conference on Robotics and Automation.

Drones can't be made infinitely smaller, due to the way conventional aerodynamics work. They wouldn't be able to generate enough lift to support their weight.

But hummingbirds don't use conventional aerodynamics and their wings are resilient.

"The physics is simply different; the aerodynamics is inherently unsteady, with high angles of attack and high lift. This makes it possible for smaller, flying animals to exist, and also possible for us to scale down flapping-wing robots," Deng explained.

The robots have 3D-printed bodies, wings made of carbon fibre and laser-cut membranes. The researchers have built one hummingbird robot weighing 12 grams, the weight of the average adult Magnificent Hummingbird and another insect-sized robot weighing 1 gram. The hummingbird robot can lift more than its own weight, up to 27 grams.

Designing their robots with higher lift gives the researchers more wiggle room to eventually add a battery and sensing technology, such as a camera or GPS. Currently, the robot needs to be tethered to an energy source while it flies - but that won't be for much longer, the researchers say.

The robots could fly silently just as a real hummingbird does, making them more ideal for covert operations. And they stay steady through turbulence, which the researchers demonstrated by testing the dynamically scaled wings in an oil tank.

The robot requires only two motors and can control each wing independently of the other, which is how flying animals perform highly agile manoeuvres in nature.

"An actual hummingbird has multiple groups of muscles to do power and steering strokes, but a robot should be as light as possible so that you have the maximum performance on minimal weight," Deng said.

Robotic hummingbirds wouldn't only help with search-and-rescue missions, but also allow biologists to more reliably study hummingbirds in their natural environment through the senses of a real robot.

"We learned from biology to build the robot, and now biological discoveries can happen with extra help from robots," Deng concluded.