Engineers at Purdue have built a flying robot to mimic one of the most expert flyers in the natural world: the hummingbird.
Drones wish they could fly with the agility and grace of the biological family Trochilidae, which includes all 357 types of hummingbirds. Boasting the flying capabilities of birds and the hovering abilities of insects, they represent an intersection of flying philosophies that scientists are eager to unlock. Hummingbirds could lead to leaps forward for search-and-rescue drones, commercial filming robots, military use, and any other flying venture that is punctuated by quick, unexpected stops and starts.
The Purdue engineers trained their robot through an algorithm based on various techniques that hummingbirds from the Andes to America use every day. After going through the training, the robot has an understanding, so to speak, of when to pause and when to take flight. Even more impressive? The robot can’t actually see. It senses by touching surfaces, with each touch altering an electrical current.
“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,” says Xinyan Deng, an associate professor of mechanical engineering at Purdue, in a press statement.
Deng and her team developed the project over years, spending multiple summers in Montana documenting the state’s several species. They studied the way hummingbirds seemingly defy conventional aerodynamics, making moves that current drones would find impossible due to their size limitations.
“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 says.
Studying the hummingbirds has paid off. Using sturdy materials, Deng and her team built the robots to be even smaller than the birds without compromising their flight. The tiny fliers have 3D-printed bodies with wings made of carbon fiber and laser-cut membranes. The hummingbird robot weighs 12 grams, around the size of the average adult Rivoli’s hummingbird, a common species in the United States.
While the scientists used the birds as an inspiration, the bots can also deviate from biology. “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 maximum performance on minimal weight,” Deng says.
Right now the robots have certain limitations. Although they only require two motors and can control each wing independently of the other, they have no independent power source and their flying is tethered. Cutting the cord to allowed extended flight is the next step for the project.
Animals have long been inspirations for technology, starting with Leonardo da Vinci studying birds and how they fly. Other animal inspirations have come from caterpillars, fish, and spiders. Meanwhile, scientists are still working on building a robot that can compete with ants.
Originally published on Popular Mechanics