Highly sensitive bio-inspired sensor for fine surface exploration and characterization

Abstract

Texture sensing is one of the types of information sensed by humans through touch, and is thus of interest to robotics that this type of information can be acquired and processed. In this work we present a texture topography sensor based on a ciliary structure, a biological structure found in many organisms. The device consists of up to 9 elastic cilia with permanent magnetization assembled on top of a highly sensitive tunneling magnetoresistance (TMR) sensor, within a compact footprint of 6×6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . When these cilia brush against some textured surface, their movement and vibrations give rise to a signal that can be correlated to the characteristics of the texture being measured. We also present an electronic signal acquisition board, used in this work. Various configurations of cilia sizes are tested, with the most precise being capable of differentiating different types of sandpaper from 9.2 μm to 213 μm average surface roughness with a 7 μm resolution. As a topography scanner the sensor was able to scan a 20 μm high step in a flat surface.