SoylentNews

upstart writes:

Subsurface tactile tomography can detect details beneath a material's surface:

The human fingertip is an exquisitely sensitive instrument for perceiving objects in our environment via the sense of touch. A team of Chinese scientists has mimicked the underlying perceptual mechanism to create a bionic finger with an integrated tactile feedback system capable of poking at complex objects to map out details below the surface layer, according to a recent paper published in the journal Cell Reports Physical Science.

"We were inspired by human fingers, which have the most sensitive tactile perception that we know of," said co-author Jianyi Luo of Wuyi University. "For example, when we touch our own bodies with our fingers, we can sense not only the texture of our skin, but also the outline of the bone beneath it. This tactile technology opens up a non-optical way for the nondestructive testing of the human body and flexible electronics."

[...] When we touch something with our fingers, the skin experiences mechanical deformation such as compression or stretching, which triggers mechanoreceptors to send out electrical impulses. These impulses travel through the central nervous system to the brain's somatosensory cortex. The brain integrates those electrical impulses to identify the features of the object that we touch. That tactile feedback enables us to recognize a material's shape, surface texture, and stiffness or softness.

The smart bionic finger mimics this feedback system. A metallic cylinder mounted on top of the finger serves as the contact tip, while carbon-fiber beams serve as tactile mechanoreceptors (the sensing unit). These are connected to a signal-processing module. The finger "scans" the target object's surface by periodically applying pressure, akin to a poke or a prod. This compresses the carbon fibers, and how much the material compresses conveys information about its relative stiffness or softness. That information, along with where on the surface it was recorded, is then sent to a computer, which translates the data into a 3D map.

Journal Reference:
Yizhou Li, Zhiming Chen, Youbin Chen, et al., A smart bionic finger for subsurface tactile tomography [open], Cell Rep, 4, 2, 2023. (DOI: 10.1016/j.xcrp.2023.101257)

Original Submission