Abstract

Dielectric elastomer actuators (DEAs) have gained increasing attention over the last decades and have been widely developed for applications fields such as robots, aerospace, biomedicine due to the fast response, high energy density, light weight, and low cost. However, the task of modeling of DEAs is typically challenged in the presence of the nonlinear features, time-independent viscoelastic behaviors, complex electromechanical coupling, etc.
To address such a challenge, a free-energy based model for DEAs moving in vertical direction is proposed, in an effort to investigate the physical properties of DEAs in this research. The developed model is based on the principle of nonequilibrium thermodynamics, where the Gent model and generalized Maxwell model are applied to describe the free energy and viscoelastic behavior of DEA, respectively. Unlike the existing modeling methods, this research narrows the focus on the inertial force and viscoelasticity which leads to DEA’s instability.
After that, the free-energy based model is simulated in MATLAB and the several sets of experiments are implemented by setting various driving voltage amplitudes and frequencies. According to the experimental data, the undetermined parameters of the model are identified by using differential evolutionary algorithm. The comparison of the model simulation and experimental results supports the validation of the proposed free-energy based model.