Dynamic modelling for the control of reinforced dielectric elastomer actuators for post-paralysis facial movement restoration

Abstract Dielectric elastomer actuators (DEAs) stand out as versatile devices with promising applications. Their use has been proposed as artificial muscle implants, aiming to replace paralyzed facial muscles and restore the corresponding movements. By reinforcing DEAs with unidirectional fibres, substantial uniaxial deformations can be induced, resulting in previously reported strains up to 75% higher than isotropic DEAs. In this work, the control of the actuator is explored by investigating the dynamic electro-viscoelastic response of a dielectric elastomer with transversally isotropic properties. A model for anisotropic viscoelastic dielectric elastomers is proposed, which is employed to describe the actuator’s dynamic response and design a closed-loop controller in order to achieve a precise actuation of the facial prosthesis. The model is validated with two types of input signals. The control system demonstrated its efficacy in minimizing error and improving actuation performance. The designed prosthesis showed a root mean square error of 2.06% in response to electromyography signals recording movement on the zygomaticus major muscle responsible for smiling.