A group of researchers from Iowa State University created tiny soft “feelers” which will allow tiny robots to manipulate very delicate and tiny objects, without damaging their structure. These “feelers” which are an ideal solution for automatic and semi-automatic performing of surgeries at the microscopic level, are capable to take and hold an ant, without injuring the brittle body. Besides, in the course of experiments, new feelers were capable to take and hold tiny parts of fish caviar which are easily deformed and damaged in the attempts of manipulation by firm tools, for example, tweezers in an integrity and safety.
It should be noted that the designs made of solid materials that make them vulnerable to the blows, scratches, breaks resulting from collision with obstacles, falling and other influences, is possessed by the majority of robots created nowadays. Therefore, more and more researchers are engaged in the development of robots made of soft and elastic materials prototypes that are found in octopuses, different types of worms and other invertebrate live organisms having soft bodies. Such soft robots are rather resistant to many types of damages, they are capable to overcome obstacles and to get into such places which are inaccessible to the robots having a rigid design.
However, miniaturization of soft robots is a very difficult business, after all, such robots usually move by means of compressed air or pressure of hydraulic liquid which spread through the networks of tiny channels penetrating their bodies and extremities. Nevertheless, researchers from Iowa managed to successfully solve a problem of miniaturization of soft technology, the prototypes of which are the trunk of an elephant, extremities of an octopus and tails of some animals.
The “feelers” created by researchers represent hollow tubes, from 5 to 8 millimeters long, that is compared to the length of a body of a large red ant. Each tube has thickness of walls from 8 to 32 microns, and the cavity, with a diameter from 100 to 125 microns, that absolutely not much exceeds the thickness of a human hair. To create such tubes, researchers lowered the thinnest wires and slices of an optical fiber to get liquid silicone. When silicone hardened, elastic covers were removed from the bars and established in the necessary places. For pressure management in hollow tubes during the experiments researchers used medical syringes acting as pneumatic pumps.
The hollow canal was located not strictly on the center of a tube when preparations were taken from a liquid solution, they were placed horizontally and the part of liquid was displaced down, doing one part of a tube thicker, than another. When pressure is created, the thinner part is bent more strongly, than thicker, forcing all the tube to be displaced in a ring.
Under usual conditions, such tiny silicone tubes are bent only once after the creation of pressure in them, are deformed and do not get back to the initial form. The researchers bypassed this trouble by means of tiny rings from silicone rubber, put on tubes, outside of which performed a role of the returnable springs restoring an initial form of a tube.
These silicone feelers could “embrace” and hold an ant, where its “waist” has width of about 400 microns, without injuring his body. It means that by means of such manipulators, tiny medical robots will be able to work with the thinnest blood vessels, nervous fabrics, embryos and other extremely fragile parts of a human body, without deforming them and without making any damage to them.