CNT-based sensor arrays for local strain measurements in soft pneumatic actuators

Abstract

Soft robotics is a recent trend in engineering that seeks to create machines that are soft, compliant, and capable of withstanding damage, wear and high stress. Soft pneumatic actuators (SPAs) are a key element of soft robots, and their elastomeric substrate enables generation of sophisticated motion with simple controls. Although several methods for fabrication, material selection, and structure design have been investigated for the construction of SPAs, limited attention has been paid to the integration of distributed sensors for performing localized measurement. Carbon nanotubes (CNTs) are molecular-scale tubes of carbon atoms with remarkable mechanical and electronic properties, showing potential application in sensing devices. In this paper, we present the design, fabrication, and testing of a novel type of CNT-based sensor array combined with silver nanowires for measuring localized strain along the bottom layer of a SPA. Simulation and experimentation have been performed in order to analyze the soft actuator deformation during bending. The results demonstrate the promise of the proposed SPA with integrated strain sensing, which lays groundwork for a myriad of applications in grasping, manipulation, and bioinspired locomotion.

Carbon fibre based flexible piezoresistive composites to empower inherent sensing capabilities for soft actuators

“…The electrode along the gauge length of the sample was then formed via a conductive carbon grease which was able to act successfully as an electrode during the application of a high strain (410%); which is typical of the strain levels experienced by a soft pneumatic actuator. 36,37 Fig . 3 shows a variation in conductance and phase angle with frequency as a function of mechanical strain for composites with 10 vol%, 15 vol% and 20 vol% of carbon fibre.…”

Pneumatic actuator and flexible piezoelectric sensor for soft virtual reality glove system

“…Because the soft actuators are usually made of flexible materials such as polymers, they have a high strain density and are easy to fabricate as per the desired shape 52,53 . In addition, flexible actuators with relatively simple mechanisms perform multiple degrees-of-freedom motions that can be handled by complicated control systems and large-scale components of hard machines 54–57 . Owing to its advantages, soft actuators have already been utilized in various fields, including medical and wearable applications 44,53 .…”

3D printing of highly stretchable hydrogel with diverse UV curable polymers

“…6B shows the printed SPA with the hydrogel sensing circuit highlighted in pink color. In comparison with previously reported approaches (see table S2) (45)(46)(47)(48), we only need one single step to fabricate the SPA with strain sensor due to the strong interfacial bonding between the UV curable hydrogel and elastomer. To achieve the relation between resistance and deformation, we print the hydrogel sensing circuit on an elastomer substrate.…”