By Jason Arunn Murugesu
Chin et al., Sci. Robot. 5, eaba2386 (2020)
A drone with flapping wings that can make quick turns like a bird could one day be used to monitor crowds as well as crops in fields.
The drone consists of a motor and a battery attached to a set of X-shaped wings made from polyurethane film and carbon fibre (see video, below). It also has rear stabilising fins made from expanded polystyrene.
Yao-Wei Chin at Nanyang Technological University in Singapore and his colleagues designed the drone to overcome many of the problems faced by previous robots with flapping wings. These aren’t able to hover because doing so requires too much energy, he says.
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“Being able to hover and make quick turns requires excess thrust,” says Chin. “Our prototype has an excess thrust of about 40 per cent of its body weight which allows it to climb fast.”
This excess thrust is achieved by maximising the drone’s energy efficiency. Its wings have nylon hinges, which minimise wobbling and help recover kinetic energy lost during flapping.
The robot weighs just 27.5 grams and can fly at speeds of up to 8 metres per second. It lasts up to 8 minutes in the air on a single battery charge.
Chin says the drone is safer than those with rotary wings. “Its wings are slow and flexible and so do not risk cutting people,” he says. It could also be used to monitor crops easily without fear of damaging them.
“Flapping drones may be more tolerant to crashes, like how a fly bounces off the window in a way that a quadcopter cannot, and have better stability in gusty conditions,” says Richard Bomphrey at the Royal Veterinary College in London.
“More focused research on the subtleties of how living models achieve such feats can reveal yet more elegant routes to the sublime performance we observe in the natural world,” he says.
Journal reference: Science Robotics, DOI: 10.1126/scirobotics.aba2386
