Sea anemone-inspired grasper is simple but effective
Sea anemones are essentially soft-bodied tubes, that are capable of capturing a wide variety of prey items simply by engulfing them. Chinese scientists have now copied this concept in the form of a robotic grasper, which could prove to be simpler yet more dextrous than regular mechanical-finger-style models.
The prototype device was developed by researchers from the Southwest University of Science and Technology, and Tsinghua University.
It's known as a bionic torus, and the bulk of it takes the form of a liquid-filled cylindrical rubber bladder. Essentially, it's like a thick vertically-oriented sleeve with inward-facing and outward-facing skins, with the liquid being contained in the space between those skins – just to clarify, the inside of the cylinder formed by the torus is open at both ends, and is not liquid-filled.
That said, a ring is attached to the torus' inner skin, on the inside surface of the cylinder. When the open bottom end (or "mouth") of the torus is placed around an object, a rod that's attached to the ring is used to pull it upwards. The ring thus pulls the inner skin up with it, causing the outer skin at the bottom of the torus to roll inwards. As it does so, that skin crimps and fattens up, gently grasping the object from all sides.
This process can be continued until the item is completely "swallowed" by the torus. When it's time for the object to be released, the inner ring is simply pushed back down, causing the skin to roll back out. While all this is going on, the torus is held in place by a secondary outer ring that's attached to its outer skin part-way up.
According to the scientists, a production version of the device should be cheap and easy to manufacture, plus it ought to be capable of grasping articles of various sizes, shapes, weights and materials.
Additionally, it should work well in narrow spaces or high-pressure undersea environments, where traditional graspers might be hampered. It may even be possible to create a nanoscale version of the torus, which would be capable of grasping and releasing individual cells.
The research is described in a paper that was recently published in the journal Applied Physics Letters.