Signal evaluation and measurement techniques in a single cell hybrid tactile sensor for large object manipulation

Abstract

It is noted that tactile sensors based on piezoelectric active surfaces require complex and advanced analog and digital signal processing circuitry in order to provide the best evaluation of the information resulting from the mechanical action of the manipulated object. Following a complete analysis of the hybrid structure and functionality of two previous realizations, the authors have recognized the feasibility of designing and building a new type of analog processing stage to enhance the sensor performance. The sensing area is realized using PVF/sub 2/ piezoelectric film deposited on three facets of a truncated tetrahedron in which the mobile element is allocated. The hybrid microelectronics for the analog and digital signal processing is built near the active surface in order to reduce noise and interference created by the industrial environment in which the device is designed to work. The design of the charge amplifiers and A/D (analog-to-digital) conversion block is optimized to provide a high-precision, three-dimensional analysis of force actions. The accuracy of measurement procedures requires the development of particular circuit topologies providing a sufficient number of signals related to mechanical effects. In order to achieve this result, a differential charge amplifier circuit has been developed. A deep analysis of functionality and dynamic response of the system under normal and limit conditions has been provided. >