Parameters identification method for viscoelastic dielectric elastomer actuator materials using fractional derivatives

Abstract

Since dielectric elastomer actuators are commonly used as artificial muscles, different approaches in material parameters identification have been used. Most dielectric actuators are parametrized with the help of continuum mechanics. Alternatively, rheological models can be used. Unfortunately, in basic rheological models, frequency dependence of viscoelastic materials cannot be obtained with a single equation. In order to obtain frequency dependences of viscoelastic material, fractional Kelvin-Voigt model is used. Fractional Kelvin-Voigt model can be applied for parameters identification in case of dynamical or cyclical excitation with different frequencies and for creep and stress relaxation analysis. Basic Kelvin-Voigt is limited on specific frequency and on creep. It cannot provide stress relaxation. Fractional Kelvin-Voigt model can further be used for fractional control. All previous work dealing with this subject is focused on analysis of material properties. Our contribution and novelty is in preparing governing equations for development control algorithms for dielectric elastomer actuators.