Development of Wearable Tactile Sensor Based on Galinstan Liquid Metal for Both Temperature and Contact Force Sensing

Abstract

F1exible tactile sensors have the ability to measure the contact force and recognize object’s surface texture, and have been widely utilized in biomedical and soft robotics. For tactile sensing in manipulation, accurate temperature and force sensing are two important parameters and are technical challenging. This paper presents the structural design and fabrication method of a thin-film wearable tactile sensor with microfluidic channeled filled with galinstan liquid metal as the sensing element for both temperature and force measurement. Characterization tests showed that the developed tactile sensor has relatively high sensing performances, the sensitivities for force and temperature sensing are 0.016 $\Omega/\mathrm{N}$ (from $0\sim 10\mathrm{N}$) and 0.004 $\Omega/^{\circ}\mathrm{C}$ (from $25 \sim 60^{\circ}\mathrm{C}$). Then these tactile sensors are worn on a hand thumb and index finger to measure the contact force and temperature when grasping of a cup of water with different temperatures. Results showed that the generated force and temperature can be accurately measured by the utilized both wearable tactile sensors. Hence, the developed thin-film tactile sensor based on liquid metal has the potential to measure multimodal tactile information for the real applications in flexible and wearable electronics, soft robotics, and intelligent prosthetics.