Of the plethora of flyers in the animal kingdom, bats possess unrivalled agility and manoeuvrability in the air. Now a trio of scientists from the US has recreated the anatomy of these flying mammals to produce “Bat Bot”, a self-contained and autonomous flying robot prototype which could one day be used in situations such as disaster relief efforts and construction work.
The University of Illinois at Urbana-Champaign’s Alireza Ramezani and Seth Hutchinson along with Soon-Jo Chung from Caltech unveiled their prototype of the Bat Bot, also known as B2, in Science Robotics.
A bat’s incredible flight control is largely thanks to its wings, which have more than 40 active and passive joints, that allow them to quickly and easily manipulate their shape.
And it’s no surprise they have long inspired scientists and engineers, as their ability to move goes far beyond the simplistic up-and-down flapping or dangerous blade-spinning motions seen in current flying machines.
Still, previous attempts to replicate bat-like flying have focused heavily on the skeletal anatomy of the animal – resulting in robots too bulky to fly.
So Ramezani, Chung and Hutchinson focused on the essential components of a bat’s wing stroke, including its shoulder and elbow movement, wrist bend and a side-to-side tail swish.
To replicate these motions, the trio constructed B2’s joints using 3-D-printed ball-and-socket structures, used lightweight carbon fibre in place of bones and popped micro-motors on the device’s “backbone” to power and control the skeleton.
Finally, the group covered B2 with an ultra-thin (56-micrometre) durable silicone skin designed to replicate the membrane of a bat’s wing, which brought the total weight of the craft to 93 grams.
Ramezani notes that this silicon skin gives B2 a particularly significant aerodynamic advantage over other flapping robot designs that rely purely on an up-and-down stroke.
“Our Bat Bot utilises the whole area of the wing as a flight control surface, the use of the silicone-based membrane skin allows the robot to morph the wing structure in flight and in mid-air without losing a smooth aerodynamic surface,” she says.
To test their new aerial robot, Ramezani and her team successfully ran B2 through a number of different flight scenarios in a large indoor pavilion, including taking off, banking turns and a sharp diving manoeuvre.
The technology used in B2, they say, offers a number of advantages over that of current aerial robot. These include better energy efficiency, reduced noise pollution and a lower threat of physical harm to people in collisions due to the machine’s lightness and lack of propellors.
Hutchinson explains that robots such as B2 could be useful in several areas including surveying active construction sites, delivering medicine to elderly residents in multilevel homes and assessing disasters such as the Fukushima nuclear accident.
“The high manoeuvrability of these robots and the longer flight time that they have should make it possible to really advance beyond what the current state-of-the-art is in robot applications for first responder assistance or disaster response,” he says.
For now, though, Ramezani and her team are currently working to make B2 more viable for real-world use, such as refining the machine’s hardware to better protect its sensitive electronics from, for instance, bad weather.
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