Over the years, we've heard about multiple systems that copy the structure of gecko feet in order to pick up delicate objects without breaking them. Korean scientists have now taken things further, by adding a means of harmlessly letting go of those items.
If you've ever wondered how geckos are able to walk straight up walls or across ceilings, it's because their foot pads incorporate millions of microscopic hair-like projections called setae. These temporarily bond with surfaces at a molecular level, due to what are known as Van der Waals forces.
Inspired by those foot pads, researchers previously developed a dry adhesive that replicated the setae with tiny mushroom-shaped structures. While that material was good at adhering to fragile objects and lifting them up, it couldn't always release them without causing some damage.
That's where the new technology comes in.
Scientists from South Korea's Kyungpook National University and Dong-A University incorporated the mushroom-like structures into a soft silicone gripper, which was mounted on the end of a robotic arm. That gripper easily adhered to and lifted a delicate glass disc off a sloping surface without breaking it, as would normally be the case.
Once it came time to release that disc, however, the gripper was simultaneously lifted up and twisted. This combination of movements allowed it to detach from the glass with a 10-fold reduction in the amount of force that would otherwise be required. As a result, no damage occurred.
And just for reference, geckos release their grip on surfaces simply by lifting their feet forward.
"We expect our research will garner significant interest from the industry, since many companies are very interested in using dry adhesives for temporary attachment and movement of components, especially in robotic applications," said Kyungpook researcher Sung Ho Lee.
The study is described in a paper that was recently published in the journal Science and Technology of Advanced Materials.
Source: STAM Hub
