The device paws gecko prompted the solution of the ideal grip for the legs of the robot

Nature again prompts solutions to designers. The paws of the gecko 60 years ago have already prompted car engineers to tread design for tires (Lamels). Now Stanford mechanical engineer Mark Kutkosky used the material based on the device of the gecko's paws to create a Stickybot robot that could climb any surface.

Just as a small reptile can vertically climb on smooth glass, Stickybot can climb on smooth surfaces thanks to the device legs, created in the image of the complex legs of the gecko.

Mark Kutkosky, Stickybot's lead designer, a professor of mechanical engineering and co-director of the Design Engineering Center, has worked with scientists around the country for the past five years to build such robots.

After developing robots that could climb a rough vertical surface, such as brick walls and concrete, Kutkosky switched to smooth surfaces, such as glass and metal. And then he remembered the geckos: "In addition to the slow and inefficient method of suckers, another solution is to use a dry hitch, which is used by geckos."
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The wonders of the feet of the gecko

The toes of the gecko contain hundreds of valve-shaped ribs, called lamellae. Each rib contains millions of bristles that are 10 times thinner than human hair. Under the microscope, you can see that each hair is divided into smaller strands called spatulae, which makes them look like split hair. These threads are so tiny (a few hundred nanometers) that they interact with surface molecules.
The interaction between the molecules of the threads of the gecko's paws and the surface causes a molecular attraction, called van der Waals forces . A gecko can hang and hold all its weight on one paw, pressing it against the glass, and then easily disconnecting it. They only hold if you pull in one direction - their fingers are a kind of one-sided glue, says Kutkos.

Gecko paw robots

This method is important because it does not require much effort to attach and detach the leg of the robot.
“Other methods are like walking with chewing gum on your legs: you must make an effort to squeeze your foot and then just as much effort to tear it off. This method is similar to hooking and unhooking, ”says Mark.
After realizing this, Kutkosky and his team wondered how to get artificial materials for robots with the same effect. They tried with rubber-like material with miniature polymer hairs made from mold.

Designers placed this material on the legs of the robot, which are the size of a child's hand, and the robot could easily climb the surfaces, resembling a mechanical lizard.

The latest versions, developed in 2009, have a two-tier system, similar to the lamellae and setae of the gecko. “Hair” has become even thinner than in the first embodiment - about 20 microns, which is five times thinner than human hair. These versions withstand even higher loads and allow Stickybot to climb surfaces such as boards, glass and metal.

Such robots can be useful for accessing dangerous or hard-to-reach places.

Future

The new task of the team is to expand the use of material for human use. The technology, called Z-Man, is already in development.

Kutkosky and his team are also working on a new version of Stickybot, which will be able to turn during lifting: since the material clings only in one direction, it is necessary to turn the legs. For this, he will have turning ankles, like those of geckos. Take a look at the paws of a gecko going downside down - they are upside down. So it should be, otherwise he will fall.

This project is funded by the National Science Foundation and the United States Department of Defense Advanced Defense Research Projects Agency (DARPA). The research is described in an article published on August 2 in Applied Physics Letters - “The Effect of the Form of Fibrils on the Adhesive Properties”.

Source: Stanford News Service