Piezo-Resistive Pressure and Strain Sensors for Biomedical and Tele-Manipulation Applications

Abstract

Nowadays, the demand for flexible and wearable devices is significantly increasing. Thereby, sensors based on carbon materials are gaining importance due to their high flexibility, sensitivity and medical compatibility. Precisely, nanocomposite based pressure and strain sensors present an interesting potential of applied force detection that helps to build the basis for body attached sensor networks. These sensor principles based on polymer carbon nanotubes composites (PCN) will have the capability for tracking finger movements, gestures and grasping. Therefore, several studies are explored in hand muscle rehabilitation, sign communication and robotic telemanipulation. This chapter reviews developed carbon materials sensors and integrated solutions for hand gestures/forces detection in the biomedical application and robotic telemanipulation. In this context, a novel PCN strain and pressure sensors were presented and investigated. An SBS (styrene-butadiene-styrene rubber)/C-TPU (conductive thermoplastic urethane) strain sensor with 1 mm as the diameter is developed. The proposed sensor shows promising sensitivity and stretchability performances with up to 50% of strain and gauge factor equal to 24. In the other part, Poly-Dimethylsiloxane (PDMS)/Multiwalled carbon nanotubes (MWCNTs) pressure sensors are investigated. The results demonstrate excellent sensing performance e.g. fast response to detect low pressure, high durability after 100 cyclic loading/unloading test and high sensitivity up to 670 kPa. Moreover, a hybrid hand motion detection system was implemented for hand rehabilitation and gestures detection. The proposed sensors were attached to a glove that leads to the monitoring of fingers’ movements and the palm pressure distribution.