When I was a senior at Berkeley over a decade ago, I took an awesome class on comparative animal physiology with Professor Bob Full. During that time he was profiled by Wired for his work on animal locomotion… or as I remember it, gecko feet and cockroaches running on treadmills 🙂
People often refer to biological inspiration as biomimicry, but rather than slavishly aping nature, he argued that it’s far better to extract her best elements and, where possible, blend them together:
Think of a robot with the sprawled posture of a crab, the quick-moving legs of a cockroach, the complex coordination of a millipede, and a scorpion’s ability to move in all directions, over rough terrain. As far as Full is concerned, there’s no reason why we can’t improve upon nature. All we need to do is look at nature with a discerning eye — and then think sideways.
“Evolution isn’t a perfecting principle; it works on the principle of ‘just good enough,’” he told Wired in 2002. “If you really want to design something for a task, you have to look at the diversity of organisms out there and then get inspired by principles.”
Bio-inspiration is all the design rage right now (and “biomimicry” has become a hot, catch-all word): from radiation-reducing materials modeled after moth eyes to biomimetic principles integrated into a Haitian orphanage. Here are some of the coolest examples of technology inspired by animals — specifically vertebrates, just to narrow it down — that I read about this year. Some are in development, and others are just ideas being tossed around because scientists discovered something new about an animal and can’t wait to apply those principles to something we can use.
Each of their 30,000 defensive quills (which are actually stiff hair) comes with a layer of microscopic, backward-pointing barbs. Up to 800 barbs line the 4-mm stretch nearest the tip.
Using natural quills and replica-molded synthetic polyurethane quills, MIT researchers dissected the physical forces involved in the penetration/removal of quills into/from pig skin and chicken muscle. It’s all about geometry. The barbs concentrate force along the edges (like serrations on a knife). A quill only needs half the force of an 18-gauge hypodermic needle to pierce skin. Once the quill is pulled backwards, the barbs flare out, snagging tissue fibers. Barbs render a quill four times harder to pull out once they’re embedded.
Some ideas for medical devices include: hypodermic needles that penetrate easily (i.e. less painfully) and resist buckling, wound dressings with tiny barbed needles that hold tight onto skin, and barbed staples to hold surgical incisions shut. [PNAS via Nature]
2. Wandering albatross (Diomedea exulans)
Once in the air, this heavy animal performs a flying trick involving repetitive up and down maneuvers, sometimes dipping to the water’s surface, and all in the face of crazy wind speed. This type of flight is called dynamic soaring, and an albatross has four phases of flight: a windward climb, a curve from windward to leeward at peak altitude, then a leeward descent, and finally a reverse turn close to the sea surface that leads seamlessly into the next cycle of flight.
Working with researchers at the Institute of Flight System Dynamics, an international team of biologists developed a model to simulate this flight. With proper aerodynamics and programming, unmanned aerial vehicles (UAVs) might one day stay aloft for weeks or months, allowing them to serve as surveillance nodes or radio relay links. [Via IEEE Spectrum]
These tiny bats have tongues that are lined on each side with hundreds of compressed, millimeter-long bristles called papillae (pictured right). When scientists from Brown used high-speed video to record bats feeding on sugar water, they saw how the papillae stiffened as the bats lapped up the solution. As the tongue extends, its muscles contract, squeezing blood into the tongue tip and then to the papillae, which become erect. Increasing the tongue’s surface area probably helps rake in more nectar.
4. Sea turtles (superfamily Chelonioidea)
Predators, light pollution… a hatchling’s journey to the water is tough. And there’s another, even more inherent challenge: walking on sand with flippers best used for swimming.
To understand how hatchlings move on soft terrain, Georgia Institute of Technology researchers created FlipperBot (FBot for short) based on footage of hatchlings on the coast. FBot revealed how they exert a force that propels them forward, without simply causing their limbs to sink into the sand. Turns out, the flexible “wrist” of a turtle helps reduce such slipping, and prevents it from winding up with a snootful of sand. [Bioinspiration and Biomimetics via Science].
5. Cheetah (Acinonyx jubatus)
In treadmill tests, the 70-pound cheetah robot (pictured below) designed by MIT researchers wastes very little energy as it trots continuously for up 90 minutes at 8 km per hour. The key to its streamlined stride: lightweight electric motors, set into its shoulders, that produce high torque with very little heat wasted. The motors can be programmed to quickly adjust the robot’s leg stiffness and damping ratio (or cushioning) in response to outside forces such as a push or terrain change. To find people or perform emergency tasks, like in the Fukushima disaster, it’d be useful for robots to be autonomous and capable of running for hours to search larger areas. [Via MIT News Office]
And let’s not forget about the wee cheetah. Three years in the making, “Cheetah-cub” is 23 cm long and 1 kg in weight. It runs about 5 kph, can descend steps up to 20% its leg length, and attains speeds seven times its body length per second. Modeled after a cat’s, the leg has three segments (foot, calve, and thigh) connected to motors in the body. Cheetah-cub also self-adjusts its movement as needed because three springs in each leg adapt dynamically to irregularities in its stride, Ecole Polytechnique Federale de Lausanne researchers described. [International Journal of Robotics Research via Science]
Last year, Professor Full and other Berkeley researchers presented Tailbot (pictured above), a little mobile robot with a lizard-inspired tail. When lizards jump, they don’t tip over backwards or fall flat on their faces. The secret, it turns out, is use of their tail as a mechanism for generating torque to control orientation in all three dimensions — dynamically adjusting the pitch, roll, and yaw of their bodies through tail motion.
Using a high-speed camera, the team tracked the lizards as they leaped (pictured right). To pitch forward, the lizard swings its tail upwards, and conservation of angular momentum does the rest, tilting the animal’s trunk nose-up. Torque applied through the tail yields “an instantaneous, predictable counter-torque on the body.” So, they added a 10-cm carbon fiber tail to a remote-controlled car from Radioshack. This provided control midair, but it only dealt with pitch control.
Real lizards can reorient themselves to upright no matter how you drop them. So this year, they constructed a robot with a two degree of freedom tail — by combining yaw and pitch to move the tail in a sort of circular motion, the robot can correct its angles of rotation in three dimensions. Inspiration from lizard tails could lead to more agile search-and-rescue robots. [Nature via IEEE Spectrum]
7. Clingfish (Gobiesox maeandricus)
There’s a lot out there on adhesives inspired by mussels and geckos of course, and here’s one with a funny fish! True to their name, they cling to slippery, wet, algae-covered rocks using an adhesive disc on their abdomens.
University of Washington researchers pitted 22 clingfish against eight different sizes of commercial suction cups, attaching them to a variety of surfaces in water and having a machine pull slowly at them. The clingfish blew all of the suction cups out of the water! The adhesive force of the clingfish was 80 to 230 times its body weight. On smoother surfaces, the fish held on for an hour or more. Apparently, there two forces working together: adhesion creates an area of low pressure between the rock and the disc that seals it to the surface, and friction prevents the disc from sliding around. Additionally, a ring of hairlike structures surround the disc — increasing the surface area, which increases friction to keep the suction sealed tight. [Biology Letters via Discover]
Sturdy armor has kept this tough, ancient species going for 96 million years — since the Cretaceous! Each of its scales has multiple layers — if the fish is injured, each layer cracks in a different pattern, allowing the scale to stay intact as a whole. Scales near the flexible parts of the fish (like the tail) are small, allowing the fish to bend. Those on the side are larger and more rigid to help protect internal organs; their joints fit together tightly so that each peg reinforces the next scale (rather than allowing it to flex).
MIT researchers created computer models of different scale types, and using a 3D printer, they printed a sheet of 144 interlocking scales out of a rigid material for a prototype. The team wants to develop a full suit of fish-scale body armor — rigid and strong across the torso, more flexible towards the joints — for the military that could replace the heavy Kevlar ones being used. [Via New Scientist]
- UltraCane uses ultrasonic waves like bats to reveal the location of obstacles for blind and visually impaired people.
- WhalePower‘s blades for fans and turbines are modeled after the humpback whale.
- Computerized fish fins from BioPower Systems convert tidal currents into electricity.
- EvoLogics makes an underwater modem for tsunami detection based on vibrations from marine mammal communication.
- There’s an anti-bacterial surface (for restrooms, countertops, medical devices, pacifiers) based on shark skin patterns by Sharklet.
- Boston Dynamics makes all sorts of big DARPA-funded cats, dogs, and pack mules.
- Japan’s 500 Series Shinkansen bullet train has serrations similar to those on owl feathers to make it quiet and an aerodynamic nose cone modeled after a kingfisher’s bill.
Images (from top to bottom): Thomas Libby, Evan Chang-Siu, Pauline Jennings, PolyPEDAL Lab & CiBER/UC Berkeley; J. Glover via Wikimedia; Cally Harper in the Brainerd-Swartz Lab/Brown University; UC Berkeley; Aquarium Advice; MIT News Office