An Electric Self‐Sensing and Variable‐Stiffness Artificial Muscle

Abstract

Soft robots have better flexibility than their rigid counterparts thus offering greater adaptability to changing environments. These robots made from flexible materials are generally with low stiffness and have limited capability to perform tasks that require the application of large forces. Soft artificial muscles (AMs) with variable stiffness are promising solutions for soft robots to handle larger payloads. However, the existing actuators need to overcome their small range of stiffness variation and slow response. Further, it is difficult to integrate self‐sensing into existing actuators. Herein, a novel electric AM with variable stiffness and self‐sensing referencing smooth muscle contraction in nature is proposed. The AM consists of two pieces of soft anode mesh, a flexible cathode and a polyvinyl chloride (PVC) gel dielectric layer, where the cathode is also a resistive sensor. The stiffness variation is induced by the friction change caused by electrostatic adsorption. Compared with the existing PVC gel actuation technology, the new design integrated the dielectric and the cathode layers and combined the sensing function. Also, the rigid anode and cathode are replaced by the soft ones, respectively, which makes the AM suitable for soft robotics or wearable devices.

Polymer ionogels and their application in flexible ionic devices

“…These actuators possess advantageous features such as high stability in air, flexibility, lightweight, ease of preparation, and low cost. Consequently, they hold significant potential for applications in soft robots, 33,136–138 artificial muscles 139–142 and other related fields 143–145 . Based on their distinct working mechanisms, PIG‐based actuators can be generally classified into electrically driven and optically driven actuators.…”