No matter how good our human designs may be, evolution has had a 4-billion-year head start, so there’s no shame in copying off Mother Nature’s homework. Engineers at the University of Bristol have done just that – and even improved on it – developing a tiny flying robot that flaps its wings more efficiently than an insect, using a unique electrostatic “zipping” mechanism.
Drones inspired by birds and insects have been flapping about for years now, like Harvard’s RoboBee or the DelFly Nimble. But while they’re capable of some nifty aerial maneuvers, they usually flap by way of complex transmission systems like gears and motors.
The Bristol team’s new drone uses an artificial muscle system that they call a liquid-amplified zipping actuator (LAZA), which requires no transmission. Each of the dragonfly-sized drone’s wings is made up of an electrode sticking out from between two other smaller electrodes at the base. A high voltage is sent through each of the base electrodes in an alternating pattern, attracting the wing electrode to each one in turn. Do that fast enough and it produces a flapping motion, which is amplified by a liquid dielectric between the electrodes.
“With the LAZA, we apply electrostatic forces directly on the wing, rather than through a complex, inefficient transmission system,” said Tim Helps, lead author of the study. “This leads to better performance, simpler design, and will unlock a new class of low-cost, lightweight flapping micro-air vehicles for future applications, like autonomous inspection of off-shore wind turbines.”
The team says that the LAZA system lets users finely control the frequency and amplitude of the flapping wings, and can provide more power than mammal or insect flight muscles of the same size. In tests, it was able to fly across a room at about 2.5 km/h (1.6 mph), or 18 body lengths per second. Its flapping wings lasted over a million cycles with no drop in performance, demonstrating that it should be able to fly long distances.
The team says that the LAZA system could eventually lead to smaller and more nimble drones that could be used in environmental monitoring, exploration, search and rescue, or even plant pollination.
The research was published in the journal Science Robotics. The flapping drone can be seen in action in the video below.
Source: University of Bristol
