Fabrication of tactile sensor array using microcantilever with low-TCR nickel-chromium alloy thin film for slippage detection

Abstract

A tactile sensor has been fabricated using NiCr-thin-film strain gauge with low noise by surface micromachining and slippage has been detected by using the tactile sensor. NiCr alloy thin film of Cr: 75wt% has very low temperature coefficient of resistance (TCR) and is employed for suppressing the temperature noise and drift. The fabricated tactile sensor with NiCr thin film (Cr: 75wt%) has linear dependences of the resistance on normal and shear forces, and shows lower noise and temperature drift than that with conventional NiCr (Cr: 20wt%). Normal and shear forces measured by fabricated sensor well coincide with applied forces with errors of 3-3.5 kPa. Moreover, detection of slippage between the robotic hand and an acrylic object was detected by using fabricated tactile sensor array, and slipping condition can be judged at the rate of 76.5%.