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

A high resolution large-area array capable of resolving the three independe nt components of a 2-D triaxial contact stress profile has been developed. The array, composed of 4096 (64 x 64) individual stress sensing elements, w as constructed with a fully CMOS-compatible fabrication process, allowing i ntegration of the sensing structures with digital control circuitry. The in dividual 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. Descr iptions of the sensor structure, the required signal conditioning, and the array architecture are presented in this paper. The results of electrical a nd mechanical characterization studies are also outlined.