Stability Improvement of Tactile Sensor of Normal and Shear Stresses Using Ni-Cr Thin Film Gauge

Abstract

Tactile sensor consisted of micro-cantilevers has been developed to detect both normal and shear stresses, and have human-friendly surface. NiCr thin film is used as strain gauge having low resistance drift, although Si piezo-resistance gauge shows the large resistance drift induced by large temperature coefficient of resistance (TCR) and its output is unstable. TCRs of NiCr films prepared by vacuum evaporation and sputtering (at RT and 600°C) are 0.054%, 0.082%, and 0.0065%, respectively, and are much lower than that of Si, 0.25%. As a result, reduction of resistance drift and stabilization of the sensor have been obtained by using NiCr thin gauge.