A traction stress sensor array for use in high-resolution robotic tactile imaging

A high resolution large-area array capable of resolving the three independent components of a 2-D triaxial contact stress profile has been developed. The array, composed of 4096 (64 x 64) individual stress sensing elements, was constructed with a fully CMOS-compatible fabrication process, allowing integration of the sensing structures with digital control circuitry. The individual array elements have been shown to demonstrate linear responses to both applied normal stress (1.59 mV/kPa, 0-35 kPa) and applied shear stress (0.32 mV/kPa, 0-60 kPa). A spatial resolution comparable to the spacing of the papillary ridges of the human dermis (approximate to 300 mum) has been achieved within the 1.92 x 1.92 cm active sensing area of the array. Descriptions of the sensor structure, the required signal conditioning, and the array architecture are presented in this paper. The results of electrical and mechanical characterization studies are also outlined.