DESIGN, CHARACTERIZATION AND IMPLEMENTATION OF A GRAPHITE-BASED STRETCHABLE STRAIN SENSOR FOR SOFT ROBOTIC APPLICATIONS

Abstract

In the recent years, soft robotic actuators have generated much interest, however, few possess sensing capabilities. Here, we present a simple and convenient method for fabricating stretchable, flexible, robust, environment-friendly and economical (< $1/sensor) strain sensors that are compatible with soft actuators. The strain sensors comprise a network of graphite particles on an elastomeric substrate, thereby achieving stretchability and flexibility while maintaining conductivity. The sensors fabricated using this approach exhibit a highly repeatable and reproducible behavior. These sensors monitor micro-strains (< 1%), display fast response (< 0.5s) and, possess a gauge factor that is fairly comparable to recent state-of-the-art. To demonstrate their utility, we integrate these sensors with soft actuators that vary in material type (silicone elastomer, fabric and 3D printed thermoplastic polyurethane) as well as actuator motion (stretching and bending). With this, we are able to detect the different movements of these actuators such as flexion, extension, and elongation.