Crosstalk Suppression for Piezoresistive Tactile Sensor Arrays with a Large Resistance Measurement Range

Abstract:
One main reason for big systematic measurement deviation of two dimensional piezoresistive sensor arrays/matrices is the crosstalk effect due to the extra current paths in parallel to that through the measured resistance. Voltage feedback circuit (VFC) and zero potential circuit (ZPC) are both widely used techniques to minimize this crosstalk effect. Meanwhile, these methods have not been investigated for sensor matrices based on nano-material like multi-walled carbon nanotubes – polydimethylsiloxane (MWCNT - PDMS), where the sensor resistance value decreases dramatically from 5 MW to 20 kW within 10 N of pressure. Due to this wide resistance range, the main issues in application are not limited to the general problems of both methods such as the switch-on resistance of multiplexers controlling rows and columns, but also the higher sensitivity to non-ideal characteristics of amplifiers, limited ADC resolution and unstable PCB power supply. In this paper, we investigate the performance of both voltage feedback and zero potential circuits in a wide resistance range, to realize a high measurement accuracy for the nano-composite sensor matrices, which are becoming increasingly relevant for pressure distribution measurements.