A 'Bat Bot' takes flight
Bat wings have intrigued scientists for centuries. And now, engineers have created "Bat Bot," a small aircraft that mimics the flight patterns of the small, rodent-like flyers. Bat Bot exposes the complicated mechanics of bat flight and simultaneously provides clues into how to make better aerial drones.
Bat Bot is a remix on an ornithopter, a machine that uses flapping wings to take flight as opposed a propeller or a balloon. You may remember Leonardo Da Vinci's famous ornithopter designs. Such manned ornithopters were the forefront of aerodynamics research for hundreds of years. As the name suggests, ornithopters are usually based on bird wings, but Bat Bot is a whole different animal.
"Bats are ridiculously stupid in terms of how complex they are," said Dan Riskin, a biologist at University of Toronto Mississauga who wasn't involved in the study. "They have a shoulder that can move in all the ways that an insect one can, but then they have an elbow, and a wrist, and five fingers and a thumb that controls part of the leading edge of the wing membrane."
Earlier attempts at a bat-like flying machine failed because inventors tried to replicate the entire skeletal and muscular structure. The final devices were too heavy to fly.
So researchers at CalTech and the University of Illinois Urbana-Champaign simplified matters by focusing on the motions of a bat wing's base components: the shoulder, the elbow, the wrist and the tail. Their device's wings are formed from a single super-thin membrane made of silicone. Its bones are made of carbon fibre, and its joints are 3D-printed plastic.
All of which lightens the load. Bat Bot weighs 3.3 ounces, roughly the same as a large lemon or one and a half tennis balls. The flexible wings aid aerodynamics too.
"So during the down stroke, the flexible wing fills up with air," said Seth Hutchinson, roboticist of University of Illinois during a press briefing. "And at the bottom of the down stroke, flexes back into place and expels the air, which generates extra lift. So that gives us extra time – flight time."
At a test facility, the researchers were able to get Bat Bot to perform aerial acrobatics with style, including banking and diving. The robot's joints are controlled by electric motors located in the robot's "spine," while a built-in computer records any aberrations in flight. The machine can maintain stable flight for just under 100 feet.
When asked about a future Bat Bot 2.0, Caltech researcher Soon-Jo Chung replied "I think perching upside down is actually very interesting maneuver that robotics researchers have not reproduced yet. So, hopefully we'll be the first ones doing so."
The concept isn't crazy. MIT researchers developed a glider that perches upright in 2010.
Because of its lightweight and durable construction, the Bat Bot could be used in the future to monitor construction sites and disaster areas. Robot surveillance of disaster areas has grown over the past decade. Rescuers first deployed disaster drones after Hurricane Katrina in 2005. PackBot examined the Fukushima nuclear power plant after the 2011 tsunami and subsequent meltdown.
The creators argue Bat Bot is safer to operate around people because it has soft wings rather than spinning blades.
"I am excited about the huge potential for using bat flight anatomy and biomechanics as bio-inspiration for small, silent and highly maneuverable micro-air vehicles" said biologist Nicolai Konow of UMass Lowell, who wasn't involved in the study.