Simultaneous Sensing and Actuating Capabilities of a Triple-Layer Biomimetic Muscle for Soft Robotics

Abstract

This work presents the fabrication and characterization of a triple-layered biomimetic muscle constituted by polypyrrole (PPy)-dodecylbenzenesulfonate (DBS)/adhesive tape/PPy-DBS demonstrating simultaneous sensing and actuation capabilities. The muscle was controlled by a neurobiologically inspired cortical neural network sending agonist and antagonist signals to the conducting polymeric layers. Experiments consisted of controlled voluntary movements of the free end of the muscle at angles of ±20°, ±30°, and ±40° while monitoring the muscle’s potential response. Results show the muscle’s potential varies linearly with applied current amplitude during actuation, enabling current sensing. A linear dependence between muscle potential and temperature enabled temperature sensing. Electrolyte concentration changes also induced exponential variations in the muscle’s potential, allowing for concentration sensing. Additionally, the influence of the electric current density on the angular velocity, the electric charge density, and the desired angle was studied. Overall, the conducting polymer-based soft biomimetic muscle replicates properties of natural muscles, permitting simultaneous motion control, current, temperature, and concentration sensing. The integrated neural control system exhibits key features of biological motion regulation. This muscle actuator with its integrated sensing and control represents an advance for soft robotics, prosthetics, and biomedical devices requiring biomimetic multifunctionality.

Linear sensing actuators of polypyrrole nanofiber scaffolds

“…Different fiber materials using either inert metal coatings or chemically deposited PPy coatings have been used. 22 Polyamide 6 (PA 6) multifilaments yarns coated with PEDOT:PSS gave fast actuators, 1% s À1 , and in a coiled form, the strain attains 1.67% when submitted to a potential range (PR) between 0.6 and À1.2 V. 23 The main goal is to develop "artificial muscles" like actuators with multifunctional applications, 24 as described by a recent overview. 25 Our approach here is getting more flexible materials using nanofiber scaffolds (NS) made from renewable glucose glycerin, then coated chemically with a thin conducting polypyrrole film, CNS, with additional electropolymerization of a PPyDBS film (the actuating film) on the conductive nanofiber scaffolds (PPyDBS-CNS).…”