Biomimicry, design and robotic bats
There is a strong tradition that recurs throughout the history of design; the constant borrowing from nature in an attempt to overcome the limitations of human form and foresight. It even has a name: biomimetics, or alternatively, biomimicry. Why try to reinvent nature’s “wheel”, when she has already solved many practical problems that modern humans still face? The solutions to our quandaries have often been under our noses if we would only look.
It’s an odd paradox that leading edge technology has often drawn inspiration from natural sources, established millennia ago - especially since the 1950’s when Biomimicry started to be actively pursued as design philosophy.
Do you desire to climb sheer surfaces? Well, how about some gecko-feet gloves? Do you like your fabrics and other materials to fasten together, come apart and re-fasten effectively and repeatedly? Try Velcro, inspired by the way Burrs cling to animal wool and fur. Do you you require an entity to willingly undertake tasks that are too dangerous or demanding for a human to endure? Try assembling a synthetic assistant (a robot) to do the job for you. Well that’s the dream, partly realised through large scale assembly plants for the automotive industry (and more).
It’s a lesson in humility. Your greatest proposed physical achievement has already been done elsewhere - by another species who leave you standing! There are animal superathletes, natural gears on the joints of planthoppers, and there’s also flight. Insects, birds and their ancestors had that mode of conveyance perfected whilst we were still throwing rocks at the moon (and each other).
A particularly interesting phenomena is the wholesale adoption of organic form (well, close enough) when creating new robots. Technology is at a point where really interesting things are being achieved increasingly with synthetic approximations of animalistic and humanistic forms. The DARPA funded Big Dog, Cheetah and Atlas projects spring to mind. These are all titans in their own way, imposing forms capable of feats of strength, endurance and speed - but big, fast and loud are not the only options.
A somewhat subtler, though equally interesting approach is being developed by ECE; the Electrical and Computer Engineering department of the University of Illinois whose engineers have chosen to create a robotic bat. That’s the flying mammal, incidentally, not an implement for playing cricket!
It started in 2014, ostensibly as a result of a conversation between two ECE professors (assumingly about bats and robots). The outcome lead the two luminaries (Seth Hutchinson and Soon-Jo Chung) into an investigation into the principles behind bats and robo-bats, followed by a very handy $1.5 million NSF (National Science Foundation) grant in order to realise the project. Brown University became involved and in turn received $700,000 to cover their efforts.
Two years later, the 92 gram “B2” has taken flight, and it’s a beautiful thing to see. There are no drone-like propellers to power it or tethers to hold it aloft, it flies by carving a path through the air with its wings, just like any avian - or more specifically, just like a bat. The intricate 3D printed chassis, the deft wing mechanisms and the controller electronics are impressive enough, but it’s the lower-tech membranous wings that really sell the concept. Yes, in the most elegant biomechanical act of creation, those behind B2 have gifted it with flexible skin in a homage to ancient Pterosaurs and modern bats alike.
The skin is silicone rubber, light and highly flexible, with very elastic properties that allow it to stretch up to 6 times it’s original size at only 100 micrometres thick. It is configured neatly as a single piece that is warped by actuator arms on servo motors that are mounted to the carbon fibre air-frame. This allows some of the movement and shape morphing facilitated by a fine bat skeleton, though naturally prioritised towards flight. There are no skeletal considerations towards hanging upside down and eating fruit for example; flight is all. It’s interesting how simple the skeletal structure can become with only that aim in mind.
The idea of a flying, robotic bat was not an random or zany choice, rather: conceived with a specific aim in mind. The goal is to allow project overseers to overlook construction on building sites. Though how long it would be confined to this relatively benign pursuit is anyone’s guess.
Yes, but a bat? One of many interesting things about bats is that their membranous wings cup and stretch against the resistance of air, and like elastic, are prone to bounce back into shape given a chance - on an upstroke for instance. In practice this provides extra ‘push’ on every wing beat, making flight very energy efficient. Contrast this with standard helicopter-style drone propulsion that requires constant drive to remain airborne and moving. Suddenly, bat power starts making sense for protracted circuits around developments in-progress (or for monitoring dissenting crowds perhaps?).
Safety is another factor - those in close proximity to drones risk injury from the high speed propellers. Wing motion is much slower by comparison and naturally lacks those spinning blades. Also, the B2 project features avoidance algorithms within the onboard system software. Combined with the low weight and subsequent lack of momentum, this makes the robo-bat considerably more human-friendly in operation than its established contemporaries, encouraging better techno-organic relations. As Riccardo Bevilacqua states on Robohub:
“Problems around effective communication between people and their machines – particularly about actions and intentions – arise throughout the field of robotics. They must be solved if we are to fully take advantage of the potential robots enable for us”.
[Photo by jochemy]
Tagged with: robotics, biomimicry
