Miraculous designs of nature (end part)

Within 50 milliseconds, the fly can turn perpendicular to the flight path - manipulation that will tear up every expensive jet into pieces .
> Part 1

The idea of ​​thorny lizards is not limited to water collection techniques. Rubner and Cohen are also developing a graffiti-resistant paint and a self-cleaning surface for kitchens and hospitals.

Ronald Fearing, professor of electrical engineering at Berkeley University in California, faces a special challenge. He wanted to design a fly robot - small, fast and flexible, that could be used in surveillance or finding missing people.

Robot flies

When we sat in Ronald Fearing's office, the window was expanding. If at that moment a fly flew into me, I would chase it away without thinking in my mind. But after Fearing explains why he took this tiny insect to model his tiny plane, I looked at the fly with other eyes. With 150 flaps in a second, it is as fast, flexible, able to hover in place or fly acrobatics. Within 50 milliseconds it could turn perpendicular to the flight path: An operation that would tear each expensive jet into pieces.

Electron microscopy shows why sharks are so fast: Its skin is not smooth but all spiky.Water flowing through the gaps does not cause vortex, reducing friction.Body armor of swimmers mimicking this special point of shark skin.(Photo: Robert Clark)

But one thing the designers definitely didn't do was copy the fly. Instead they have to learn the structures that make it possible, and then calculate whether those very complicated operations can be done with simpler tools.

"For example, the wings of the fly have more than 20 muscles, but there are a few chances that every five flaps will work once. Why?", Fearing asked. "And do I really need such complicated things?"

Before Fearing, neurobiologist Michael Dickinson enlarged the fly structure so that he could see its movements: He allowed a 30-cm-long plastic wing to move in a tank of 2 tons of engine oil. . Thereby he discovered that the fly wings do not simply beat up and down but follow a line like a U and rotate in a certain style.

Fearing maximized the complex joints of fly wings in nature, giving a similar pattern. The wings he designed did not have 20 muscles but they were also beaten in a U-shape. But when he asked some mechanical experts to make himself such an engine, and only allowed to weigh at most 10 milligrams, they all refused: "The last level is 10 grams, they say. But if so, only the engine is bigger than the fly."

So Fearing made his own engine: A small tube about 11 millimeters long, no thicker than a cat's beard. In addition, with a tiny laser, he created wings by cutting many pieces of polyester that are only two thousand millimeters thin. This material was rippled as soon as people only breathed in it and had to be reinforced with many carbon fiber bars. Fearing eventually succeeded.

The wings of the latest model beat 275 times a second - faster than the real insect's wings - and also created a very characteristic buzz. "Carbon fiber is obviously more capable than the insect's natural chitin," he asserted.

The first remotely controlled flight was successful. Fearing predicts that in 2-3 years the flying robot will be able to hover in place. And at some point it will fly the curves elegantly like a real fly.

Stickybot: Imitating a gecko

Gecko has 6.5 million hairs on each toe (left).Stickybot robot (right) can also climb up the vertical glass but so far not with the speed of gecko but with the speed of the snail.(Photo: Robert Clark)

Right from 350 BC Aristoteles was surprised how a gecko "could run up and down a tree, even head to the ground". What did they do to "neutralize gravity" ?

Two years ago, robot developer Mark Cutkoskys of Stanford University began to find a way to solve this ancient puzzle: Taking a gecko as a model, he designed a climbing machine named "Stickybot".

The gecko's foot does not stick, it feels dry and smooth. Its special grip ability is due to the 2 billion tiny hairs that have a pointed tip like a mortar's flight that carries on every square centimeter of the toe. Each of these hairs is only a few hundred nanometers thick - so thin that it comes into contact with the surface in a special way: thanks to the interaction between the charges of the molecules - van der Waals force.

To build the gecko leg, Cutkosky used a urethane fabric with very small, 30-micron sharp tips. Although they are 300 times larger than the hair of a gecko's leg, their grip is sufficient to hold a 500-gram robot on a vertical plane.

But it must not only stick but also be able to walk. Geckos dive on a smooth wall with a speed of up to one meter per second. They must also lift their legs gently and quickly. To find out, Cutkosky asked two biologists to help and they discovered something very important: Gecko toes only clung to the bottom when pulled back or down; as soon as the direction of rotation changes, they will separate.

Accordingly, Cutkosky also equiped robots with artificial toes that only adhered to the underside of the force in one direction and separated at the other. He then learned that the gecko was equally divided over the entire area of ​​the toes with many leg veins with branching. So he also put in the legs of the branched "ribbed" robot made of chemical fibers to divide the weight in such a way.

Success: "Stickybot" climbed on slippery flat surfaces like glass, plastic or ceramic tiles without slipping or falling, but when it reached the speed of a real gecko it took a lot of time. Unlike geckos, the dry adhesion layer on the robot's "toes" is not self-cleaning. Dust clung to them quickly and thus they lost their adhesion force.

Although it is still far behind nature, this robot has many potential applications. The US Department of Defense is considering using it for surveillance: An automated machine can secretly climb a building and observe the surrounding land with a camera. Cutkosky thinks of many civilian applications: "It would be great if" Stickybot "at any time helped save human life by going to places where people could not reach a way. simple."

Imitating nature - an arduous journey

"If" and "maybe" - are the words that most biomimicists often use to end the presentation on the biologically suggested inventions. Applications achieved so far only count on fingertips.

It's a simulated Velcro velcro from plants. Or the effect of the lotus, wash away the dirt with water particles rolling on the surface. Today, many types of wall and tile paints are produced on the same principle, but glass doors and self-cleaning toilets are still waiting.

Many strong businesses went bankrupt when trying to develop artificial spider silk before German material researcher Thomas Scheibel made a breakthrough. Why is it so difficult to apply the pattern of nature?

It is because nature is simply unimaginable and extremely complex.

The evolution of "sketching" the wings of the fly or the gecko's legs does not follow a certain purpose as the vision of an engineer. Evolution stumbles in countless random experiments over millions of generations. The result of numerous mutations and selection of successful variants often leads to strange creatures having only one purpose: to live long enough to reproduce the next generation and thereby start random experiments next.

In order for the abalone's "house" to be so hard with the least amount of material possible, 15 different proteins reacted in a very special biochemical order. Exactly how many leading scientific teams so far have not fully understood. Durable spider silk is not only thanks to the mixture of basic ingredients but also thanks to the structure of the silk webs: 600 lines weave together 7 different types of silk together.

Because of these complexities, it is very difficult to understand biological patterns. But the distance will get shorter and shorter. Thanks to microscopic tomography, electron microscopy ., biomimeticists are increasingly going into the nano world.