Inflatable squishy tubes could be used to build soft robots that move when air is pushed through them.
Robotic hands made from metal frequently end up crushing delicate objects like fruit when trying to pick them up, so researchers often experiment with making them out of gentler materials. at Princeton University and his colleagues have found that soft, inflatable tubes may just do the trick.
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The team filled various moulds with a rubber-like material called polyvinyl siloxane that starts off liquid but becomes solid and elastic as time passes. While the material was still fluid, the researchers pushed air into the moulds to create elongated bubbles.
Brun says the way the bubbles move through each of the filled moulds is crucial for determining how the hollow, flexible tubes behave after unmoulding. Specifically, as a bubble moves, gravity pulls it downwards so the resulting tube is thicker at the bottom than at the top. The researchers can also push several bubbles through the mould at different times to shape the elastic material at different stages of solidifying.
This makes various parts of the final tube bend, curl or coil differently when inflated with pressurised air. Although the pressure inside the tube was the same everywhere, the it could respond 鈥渟martly鈥�, even curling up in sequence as if it was programmed to change shape with a time delay, Brun said.
In one experiment, the researchers connected a straight tube to a loop and dangled it next to a blackberry. They pushed air through the loop so that it curled around the berry and delicately picked up the fruit.
The researchers now want to make these tubes form even more complex shapes by tweaking the chemical properties of the elastic material or by using foamy material instead. Brun presented the work at the in Washington DC on 19 November.
