Many mammals, including seals and rats, rely on their whiskers to sense their way through dark environments. Inspired by these animals, scientists working at the University of Illinois at Urbana-Champaign and Illinois’ Advanced Digital Sciences Centre in Singapore have developed a robotic ‘whisker’ tactile sensor array designed to produce tomographic images by measuring fluid flow.
The results are published today (Wednesday 05 August) in the journal Bioinspiration and Biomimetics.
“When it is dark, whiskers play a key role for animals in exploring, hunting or even just living underground” explains Cagdas Tuna, a lead author on the paper. “For example, seals can catch fish in the dark by following the hydrodynamic wake using their whiskers.”
The whisker array is constructed of five super-elastic Nitinol wires, covered with plastic straws, resulting in each whisker being about 15 cm long and 3 mm wide. Strain gauges attached at the base measure movement in each whisker, and these signals are used to build up an image of the fluid flow past the array.
“There’s no proof that animals do a similar ‘tomographic reconstruction’ in their brains,” continues Tuna. “But this shows great potential to be a useful, if unconventional, sensing system.”
The whisker array offers a strong alternative or complement to existing systems for navigating, tracking or detection in dark conditions. Future efforts to improve the imaging model to consider object content and miniaturise the system may lead to even wider uses.
“This may even find use in biomedical applications, such as cardiac surgery” concludes 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.”
Source: Steve Pritchard – Institute of Physics
Image Source: The image is credited to Institute of Physics
Original Research: Abstract for “Tactile soft-sparse mean fluid-flow imaging with a robotic whisker array” by Cagdas Tuna, Douglas L Jones and Farzad Kamalabadi in Bioinspiration & Biomimetics. Published online August 2015 doi:10.1088/1748-3190/10/4/046018
Abstract
Tactile soft-sparse mean fluid-flow imaging with a robotic whisker array
An array of whiskers is critical to many mammals to survive in their environment. However, current engineered systems generally employ vision, radar or sonar to explore the surroundings, not having sufficiently benefited from tactile perception. Inspired by the whisking animals, we present here a novel tomography-based tactile fluid-flow imaging technique for the reconstruction of surroundings with an artificial whisker array. The moment sensed at the whisker base is the weighted integral of the drag force per length, which is proportional to the relative velocity squared on a whisker segment. We demonstrate that the 2D cross-sectional mean fluid-flow velocity-field can be successfully mapped out by collecting moment measurements at different angular positions with the whisker array. We use a regularized version of the FOCal underdetermined system solver algorithm with a smoothness constraint to obtain soft-sparse static estimates of the 2D cross-sectional velocity-squared distribution. This new proposed approach has the strong potential to be an alternative environmental sensing technology, particularly in dark or murky environments.
“Tactile soft-sparse mean fluid-flow imaging with a robotic whisker array” by Cagdas Tuna, Douglas L Jones and Farzad Kamalabadi in Bioinspiration & Biomimetics. Published online August 2015 doi:10.1088/1748-3190/10/4/046018
