Two Northwestern University engineers have been studying rat whiskers to learn how mechanical information from the whiskers gets to the rat's brain.
The goal is to develop artificial whisker arrays for engineering applications.
Mitra J. Hartmann, assistant professor of biomedical and mechanical engineering, and Joseph H. Solomon, a graduate student, have developed arrays of robotic whiskers that sense in two dimensions, mimicking the capabilities of mammalian whiskers. The arrays can sense information about both object shape and fluid flow.
The arrays may be used on assembly lines, in pipelines, or on land-based autonomous rovers and underwater vehicles. The technology, Hartmann says, could also be used to extract the 3D features of almost any solid object.
Rat whiskers move actively in one dimension, rotating at their base in a plane roughly parallel to the ground. When the whiskers hit an object, they move back, up, or down. Bending the whisker activates thousands of sensory receptors in the follicle at the whisker base. The receptors, in turn, send neural signals to the brain, where a three-dimensional image is presumably generated.
Hartmann and Solomon showed that their robotic whiskers could extract information about shape by whisking (sweeping) across a small-sculpted head specifically chosen for its complex shape. As the whiskers move across the object, strain gages sense the bending and thus determine the location of different points on the head. A computer program then "connects the dots" to create a 3D representation of the object.
The researchers also showed that a slightly different whisker array — one in which whiskers were widened to provide more surface area — could determine the speed and direction fluid flow.