A smart bionic finger for subsurface tactile tomography

Bio-robot equipped with tactile sensors can simulate humans to sense surface characteristic information of an object, but acquiring subsurface information from materials remains challenging. Here, we introduce a smart bionic finger with subsurface tactile tomography capability. This bionic finger is equipped with an integrated tactile feedback system, which allows the bionic finger to respond to a force quantitatively. A series of thresholds corresponding to the forces are set up for the bionic finger to generate a layer-by-layer series of slice images of material. These slice images can reveal and reproduce the internal structure of the materials with a soft surface layer. This subsurface tactile tomography is further demonstrated by the reconstruction of a subsurface 3D profile of both artificial human tissue and an encapsulated flexible circuit system. This bionic finger, with the capability of subsurface tactile tomography, opens up a nonoptical way for the nondestructive testing of the human body and flexible electronics.