Tactile Scanning for Detecting Micro Bump by Strain-Sensitive Artificial Skin

Abstract

This letter proposes a scanning tactile sensor that amplifies the signal output of a strain gauge deformed into a wave shape and fixes the position of micro defects. In this study, we realized a thin scanning tactile sensor that is sensitive to micro bumps and can be used as artificial skin. The proposed scanning sensor consists of a simple flexible structure and a strain gauge. The inspection time needed to detect a convex shape from a wide area on a plate can be shortened by using a long strain gauge. However, the output signal is weak, making it difficult to identify the position. Parallel pins placed on the sheet increase the deformation of the strain gauges and amplify the output. We conducted an experiment to compare the output signals of the proposed sensor and a tactile sensor with strain gauge attached to a silicon sheet. Compared with a silicon tactile sensor, the output of the proposed tactile sensor on a curved surface was amplified by about 4.7 times. In addition, the output signal for a small convex shape (50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu {\rm m}$</tex-math></inline-formula> in height) was amplified about 4 times more than that of the simple strain gauge. We can easily detect micro bumps from the signal of the proposed sensor. Finally, we combined two of the proposed sensors to conduct an experiment to detect the position of micro bumps. The position of a convex micro deformation with a height of 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu {\rm m}$</tex-math></inline-formula> was precisely identified.