Flexible and Stretchable Strain Sensing Actuator for Wearable Soft Robotic Applications

TLDR

Despite the emergence of flexible and stretchable actuators, few possess sensing capabilities. The authors aim to integrate a flexible pneumatic actuator with a stretchable strain sensor to create a soft sensorized actuator and demonstrate its use in a glove for finger kinematics analysis. The actuator uses an elastomeric microchannel driven by air to bend, while a thin screen‑printed silver nanoparticle layer on elastomer provides stretchable sensing; the two are integrated to measure bending extent. The sensorized actuator detects deformations beyond 20 % with a gauge factor over 50 000, enabling real‑time detection of irregular finger movements and assessment of finger stiffness or dexterity.

Abstract

Despite the emergence of flexible and stretchable actuators, few possess sensing capabilities. Here, we present a facile method of integrating a flexible pneumatic actuator with stretchable strain sensor to form a soft sensorized actuator. The elastomeric actuator comprises a microchannel connected to a controlled air source to achieve bending. The strain sensor comprises a thin layer of screen‐printed silver nanoparticles on an elastomeric substrate to achieve its stretchability and flexibility while maintaining excellent conductivity at ≈8 Ω sq –1 . By printing a mesh network of conductive structures, our strain sensor is able to detect deformations beyond 20% with a high gauge factor beyond 50 000. The integration of a pneumatic soft actuator with our sensing element enables the measurement of the extent of actuator bending. To demonstrate its potential as a rehabilitation sensing actuator, we fit the sensorized actuator in a glove to further analyze finger kinematics. With this, we are able to detect irregular movement patterns in real time and assess finger stiffness or dexterity.