Multiple-layer cross-field ultrasonic tactile sensor

This paper presents an ultrasonic “cross-field” tactile sensor that is robust enough for use in industrial robotic applications. This sensor uses ultrasound to measure the thickness of an elastomer pad and a “cross-field” arrangement to eliminate the spurious coupling commonly found in systems that employ cross-point switching. A tactile sensor with 256 elements (arranged as a 16×16 array of 1/16"-square elements) was shown to linearly measure thickness of the elastomer pad across a range of 900 microns with a resolution of 6.8 microns. In addition, the sensor is shown to accurately measure surface normal information