Identification of a Nonlinear Dielectric Elastomer Actuator Based on the Harmonic Balance Method

Abstract

This article presents a control-oriented modeling of a circular dielectric elastomer actuator loaded with a mass. Precise dynamic position control of these actuators is a challenge, because of the high level of nonlinearities. Our model takes into account nonlinear mechanical phenomena such as hyperelasticity and viscoelasticity. The behavior of dielectric elastomer actuators is analyzed by a series of experiments on three actuators with different parameters. Furthermore, the model parameters are found using optimization procedures. To improve the performance of the optimization, the steady-state solution is found using the harmonic balance method (HBM). Compared to a forward integration method, the time gain of the HBM is significant, and exceeds two orders of magnitude when six or less harmonics are considered. The application of steady-state solver enables taking the frequency response into account for the parameter identification procedure. The results obtained from the model are compared with experiments and show an excellent agreement.