Design, fabrication and characterization of soft sensors through EGaIn for soft pneumatic actuators

At present, very few soft actuators have achieved strain and pressure sensing capabilities simultaneously. In this paper, one kind of soft strain and pressure sensors based on liquid conductive metal (EGaIn) are proposed, which can be integrated into typical soft pneumatic actuator easily for sensing functions. Here we report design models, fabrication techniques, sensing characterization and sensation experiments for the potential sensors. Especially for EGaIn-based strain sensors, sensitivity is improved greatly (up to 28.6-similar to 30.8) realized via embedded fibers, and low hysteresis (2.23%) and high repeatability (loading: +/- 0.92% and unloading: +/- 1.34%) are further demonstrated. Also, we explore a novel embedded channels-manufacturing method called lost-wax casting, which could overcome fabrication complexity, possible leakage and low manufacturing success rate dramatically. Finally, our experimental demonstration utilized the sensorized actuators to detect the profiles, sizes and softness of objects and obtained desired results like a real finger. (C) 2020 Elsevier Ltd. All rights reserved.