A Flexible Dual-mode Sensor with Decoupled Strain and Temperature Sensing for Smart Robots

Abstract

Flexible dual mode strain-temperature sensors that mimic human skin functions are highly desired for wearable devices and intelligent robots. However, integrating dual sensing characteristics into a single sensor for simultaneous and decoupled strain-temperature detection still remains a challenge. Herein, we report a flexible dual-modality sensor that uses a "neutral surface" structural design technique to integrate independently prepared temperature sensing layer (TSL) and strain sensing layer (SSL), for simultaneous monitoring of strain and temperature, in decoupled manner. TSL consists of PDMS/BaTiO3 based dielectric layer whose dielectric constant and thickness changes in response to temperature fluctuations. SSL consists of resistive type Ni80Cr20 film whose resistance changes in response to external strain. After optimizing the temperature and strain sensing characteristics of TSL and SSL, a dual-modal flexible sensor obtained has shown broad temperature sensing range (30 to 200 °C), with high temperature sensitivity (-160.90 fF/°C), excellent linearity (0.998), and highly discernible temperature resolution (0.1 °C). Additionally, the sensor also exhibits wide strain monitoring range (20 to 1000 με), good strain resolution (20 με or 0.002%), and fast strain response time (54 ms). When practically demonstrated, our sensor has successfully shown independent perception of strain and temperature, which highlights its promising application potential in the fields of smart robotics and intelligent prosthetics.