Embedded piezoresistive pressure sensitive pillars from piezoresistive carbon black composites towards a soft large-strain compressive load sensor

Soft robotics is a rapidly expanding field that aims at replacing rigid robotic components in a wide range of applications with more compliant, organic and functional components. The limited availability actuator-compatible sensors that can provide real-time feedback limits large scale implementation of these soft robots. A secondary sensing layer that encompasses the soft actuator or a sensor embedded soft actuator would enhance the suitability of soft robots in a wider range of applications. This article describes the design, fabrication and characterization of a carbon composite elastomeric force sensor, which aims to be a free standing film than can be cut into desired shape and embedded into soft robots while manufacturing for imparting self-sensing capabilities. Various concentrations of carbon black in the elastomer composite have been studied and the ideal concentration is derived. Carbon composite pillars as soft sensors with conductive tracks on top and bottom were fabricated and embedded in a soft elastomer matrix for analysing the sensor response under physical loading. The sensitivity of these sensors were identified and characterised, and were found to be capable of detecting forces as small as 0.1 N. The thin-film free-standing architecture of sensing element allows embedding the fabricated sensing element into any elastomer matrix improves the applicability of these sensors in a wide range of soft robotic applications. (C) 2018 Elsevier B.V. All rights reserved.