Dr. Tianqi and colleagues at the University of Bristol have successfully built an artificial octopus sucker for robots to lift and release rough-surfaced objects much easier and more energy-efficient.
Unlike most human made suction cups, octopus suckers have no problem when forming a seal on objects with rough, curved, or irregular surfaces, such as rocks. For a long time, it has been believed that comes from almost entirely to the soft, malleable nature of the sucker issue. However, the team at the University of Bristol has found that the mucus secreted by those suckers is also important.
They have made a device with the same cup-like shape, composed mainly of multiple overlapping layers of soft silicone, allowing it to mostly conform to the contours of rough surfaces, much like what an octopus sucker is.
Although a number of micron-sized gaps still remain between the device and the surface, the secret lies in using water to mimic octopus mucus. To fill these gaps, water is injected through an attached tube to flow into a fluidic system which forms a ring around the base of the cup. This action is much like the mucus cells forming a ring around the base of an octopus sucker.
As a result, the water fills all the minuscule gaps when the water seeps out of tiny openings in the fluidic system, making it a perfect seal. The cup is believed to be able to lift and hold the object indefinitely as pressure is constantly being maintained on the water in the tube and any small amounts leak out are instantly replaced. To release the object, simply lift one edge of the cup.
According to Dr. Tianqi, this new powerful adaptive suction strategy may be instrumental in the development of versatile soft adhesion in the future.
Octopus-inspired devices have long been known as popular to explore. In the meantime, scientists at the University of Illinois have been also working on an artificial octopus sucker of their own by using a temperature-sensitive hydrogel. The new octopus-inspired gripper is designed to pick thin sheets of lab-grown biological tissue, which shows promise for applications such as the treatment of wounds.
