Artificial whiskers borrowing principles from seals and rats have been used to build up digital images of fluid flow.
Scientists from the University of Illinois, inspired by the way mammals use whiskers to sense their way through dark environments, created an array of five super-elastic Nitinol wires covered with plastic straws about 15cm-long to mimic whiskers, which were then hooked up to strain gauges at their base.
Electronic signals from these gauges enabled the researchers to measure movement in each whisker, as motors moved them through an air stream from a hair drier and this data was then used to build up a digital image of the fluid flow past the array.
“When it is dark, whiskers play a key role for animals in exploring, hunting or even just living underground” explains Cagdas Tuna, lead author of a paper on the array published today in journal Bioinspiration and Biomimetics. “For example, seals can catch fish in the dark by following the hydrodynamic wake using their whiskers.”
The array created by the researchers uses a technique called tomography that produces a series of virtual slices through the wave of the airflow before piecing these back to together to create an image of the flow.
“There’s no proof that animals do a similar ‘tomographic reconstruction’ in their brains,” said Tuna. “But this shows great potential to be a useful, if unconventional, sensing system.”
The whisker array could provide an alternative or complementary way to navigate, track or detect in low-light conditions and the researchers' future work will aim to improve the imaging model, considering object content as well as miniaturising the system.
“This may even find use in biomedical applications, such as cardiac surgery” added Tuna. “A thin-whiskered catheter tip could be used during surgery to track the relative position inside the heart, potentially reducing the risk of injury, or atrial fibrillation.”