Analysis and design of a tactile sensor detecting strain distribution inside an elastic finger

Humans obtain complex information using different tactile receptors in the skin of the finger. Artificial tactile sensors capable of detecting complex information can be realized by imitating certain characteristics of the human finger, such as the geometry of the finger and the location of the tactile receptors. We analyze the strain distribution that occurs inside an elastic finger having a curved surface when the finger is in contact with an object. Detection of the shear strain distribution pattern is found to be important. In addition a strain distribution sensor is developed, in which strain gages bonded on thin plates are arranged at uniform intervals inside the curved surface of an elastic finger made of silicone rubber. The geometry of the elastic finger is designed by calculating the contact condition between the finger and objects with/without tangential load using FE (finite element) analysis. The fundamental characteristics of the strain distribution sensor are confirmed.