Capacitive impedance readout tactile image sensor

Abstract

The transduction of mechanical forces to representative electrical signals uses a three layer sandwich structure. The top layer is columns of compliant metal strips over a central elastic dielectric sheet. The bottom layer is a flexible printed circuit board with rows of metal strips and multiplexing circuits. Electrically, the sensor is a capacitor array formed by the row and column crossings with the middle layer functioning as a dielectric spring. A readout of the capacitor values corresponds to a sampled tactile image. The reasons for choosing this transduction method, the performance advantages of capacitive sensing and the design and integration of 64 element imagers into the fingers of a controlled compliance gripper are described.