A micro robot with delicate tentacles

DailyTechInfo based on Discovery News: Robotic Tentacles Pick Up Ant Without Crushing It 

A group of robotics researchers from the University of Iowa (Iowa State University) has created tiny soft "tentacles" that will allow miniature robots to very delicately manipulate even tinier objects without damaging their structures. These "tentacles", which are an ideal solution for automatic and semi-automatic surgical operations at the microscopic level, are able to capture and hold an ant, whose "waist" is about 400 microns wide, without damaging its fragile body. 

In addition, during the experiments, the new tentacles were able to capture and hold intact tiny particles of fish caviar, which are easily deformed and damaged when trying to manipulate them with hard tools, for example, tweezers.

It should be noted that most of the robots currently being created have structures made of solid materials, which makes them vulnerable to impacts, scratches, fractures resulting from collisions with obstacles, falls and other impacts. Therefore, more and more researchers are developing robots made of soft and elastic materials, the prototypes for which are octopuses, various types of worms and other invertebrate living organisms with soft bodies. Such soft robots are quite resistant to many types of damage, they are able to overcome obstacles and penetrate into places that are inaccessible to robots with a rigid structure.

However, miniaturization of soft robots is very difficult, because such robots usually move with the help of compressed air or liquid pressure, which are distributed through networks of tiny channels that permeate their bodies and limbs. Nevertheless, researchers from Iowa managed to successfully solve the problem of miniaturization of soft technology, the prototypes of which are the trunk of an elephant, the limbs of an octopus and the tails of some animals.

The "tentacles" created by the researchers are hollow tubes from 5 to 8 millimeters long, which is comparable to the body length of a large red ant. Each tube has a wall thickness of 8 to 32 microns, and a cavity with a diameter of 100 to 125 microns is created inside it, which is not much larger than the thickness of a human hair. In order to create such tubes, the researchers dipped the thinnest wires and pieces of fiber into a liquid silicone solution. When the silicone hardened, the elastic shells were removed from the bars and installed in the necessary places. To control the pressure inside the hollow tubes during the experiments, the researchers used conventional medical syringes that acted as air pumps.

The hollow channel was not located strictly in the center of the tube: when the blanks were removed from the liquid solution, they were placed horizontally, and part of the liquid shifted down, making one side of the tube thicker than the other. When pressure is created in such a tube, the thinner side bends more strongly than the thick one, forcing the entire tube to curl into a ring.

Under normal conditions, such tiny silicone tubes bend only once after pressure is created in them, deform and do not return to their original shape. The researchers circumvented this nuisance by using tiny silicone rubber rings worn on the outside of the tubes, which served as return springs restoring the original shape of the tube. 

With the help of such manipulators, tiny medical robots will be able to work with the thinnest blood vessels, nerve tissues, embryos and other extremely fragile parts of the human body without deforming them or causing any damage to them.

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22.06.2015