Tuesday, December 11, 2007
posted by Andrew at 4:30 AM
As if the signature of books and practice of surgery on patients is not enough, the robot can walk on water, even with the engineers at Carnegie Mellon University (CMU). What started as a project of the class, which three years ago ended insectlike mechanical robot from four to sixteen legs. The "mistake" of two to six inches long and weighs a few grams, may try next to waters, the reports IEEE Transactions on Robotics. Military service upswing for the surface tension on insects automatic dynamic viewing, the robots use water from the surface of the combined power of their legs thin as water striders, insects, which motivates the challenge.

Tension on the surface, the force that is the beautiful form of droplets to drop water, resists even breaks in the surface. That is why, for example, a thin needle to sew can appear on a sheet of paper, silk of water, and the needle is brisk, but the substance is saturated with water, and wells. This is very different from the vertical shear keeps the ships exchanged because of the difference of a vessel, the needle is on average denser than water and flows when nudged slightly downward. The experiment works better if the needle has a hydrophobic coating or impermeable as Teflon (such as the surface nonstickwanne cooking pots).

CMU water robot walkers use the motor voltage on the surface of a Teflon-coated, the legs of a few hundred micrometers in thickness and two to four inches in length to stand above the water. To move and rotate, they will use a "sculling movement, [which] in the first leg of the race is in the air, and during the race in reverse leg pushes water [but] never break the surface water," says Chief Metin Sitti. That is exactly the way the water striders move, but the maximum speed of around five meters per second, compared to several centimeters per second for this robot.

What is it for their speed? Although the robot pump their legs much faster than the insects (40 times per second, as opposed to a maximum of 10 for the insects), the trains are much shorter, and beyond, the robot hundred times heavier than insects. "If you reduce the system, you have much more energy efficient and nimble," said Sitti of insects' speed.

But an increase in speed is not the only goal, only one leg introduced water strider can 15 times the weight of the insect, a mosquito leg while on the water can be 23 times the body weight, compared with only about half a body weight after one leg robot error. Furthermore, the insects are regularly below the water surface because of the rain and turbulence, but always successfully surface. Both capabilities are impressive because of microscopic hairs on their legs, which, in addition to its hydrophobic legs, the event also acts as an air cushion buoyancy characteristics or a life jacket. Sitti tried to imitate this function with the help of hair geckos' feet on their robots' legs; micro-production of synthetic bristles can come later. Searches also can use Teflon coating, the more hydrophobic, following the example Derjenigen, based on Gore boots.

The errors "are really cheap to manufacture, because they are very simple," said Sitti, allowing for the selection of targets for many applications. In addition to its educational value and the entertainment, this robot can be used for monitoring the environment of ecosystems such as water, ponds and swamps. You can walk on water, which at one tenth of thumb, and have sensors on the information back to shore, the functioning minimalement invasive sensors, and the opening of a new form of listening.
 
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