Robots we usually see in action usually have quite big, clunky hands that look like pair of tongs. Although they are pretty usuefull in grabbing big things that are not easily broken by force, they are not very good for dealing with delicate items. Now Scientists from Iowa State University have created a new solution for dealing with small things – tentacles. In fact, these tentacles can handle things as small as an ant.
Tiny tube circles around an ant and traps it without crushing it, thus demonstrating the utility of such microrobotic tentacle. This engineering solution was created out of need. Since most robots use two fingers to lift objects, they have to squeeze it, which is not appropriate way of dealing with small, delicate items. Scientists note that tentacle wraps around the object very gently.
These are spiralling microrobotic tentacles, produced from PDMS – a transparent elastomer that can be a liquid or a soft, rubbery solid. Tentacles are just 8 millimetres long and less than a hundredth of an inch (approximately 0.254 mm.) wide. Researchers sealed one end of the tube and pumped air in and out. Because these microtubes have asymmetrical wall thickness, air pressure creates a bend. Engineers also added a small lump of PDMS to the base of the tube to amplify the bend and create a two-turn spiralling, coiling action. It seems to be a very simple and easily controlled approach to robots handling small and delicate objects, but it was exactly what scientists needed.
In their paper, scientists noted that spiralling tentacles are widely common in nature – variety of organisms uses them to grab and squeeze things. And there have been attempts to take inspiration from these tentacles, but they have not reached any significant success. Engineers further explained that “There have been continuous soft-robotic efforts to mimic them…, but the life-like, multi-turn spiralling motion has been reproduced only by centimetre-scale tentacles so far. At millimetre and sub-millimetre scales, they could bend only up to a single turn”. And it took a lot of time and efforts to create the extra turn in the microrobotic tentacles.
The engineering team had to do a lot of research and testing to reach the desired action. They had to develop new production techniques to create the microtubes, figure out a way to peel them off a production template, use computer modelling to find a way to create more coiling, which was desired for the robots in the future to be able to handle very small and very delicate objects.
Scientists jokingly said that they describe the properties of the resulting tentacle as “S-cubed – soft, safe and small”. Even though the demonstration with an ant was very impressive, robotic tentacles have much more useful applications. Scientists said that this technology is ideal for medical applications because the microrobotic tentacles cannot damage tissues or even blood vessels. However, it will take some time for robotic tentacles to reach their destined applications as more research needs to be done and robot needs to be developed as well.
Scientists say that such invention was made because of two major trends in the robotics – efforts to make robots as small as possible and to develop new materials to avoid the use of metals and composite materials such as carbon fibre. It also may find its application in hospitals of the future.