A linear parameter-varying modelling approach for dielectric elastomer loudspeakers

Abstract

In this paper, we present a linear parameter-varying (LPV) model of an electrostatic loudspeaker driven by dielectric elastomer (DE) actuators. Because of its numerical simplicity, this LPV model represents a convenient tool to develop real-time control strategies for the speaker. Starting from a non-linear reduced model of the device, we assume that the control input can be broken into two components: a small-amplitude high-frequency component, responsible for the sound generation, and a slowly-varying bias component, which can be used as a free control parameter to tune and adjust the speaker response. We thus build an LPV model, treating the dynamic response to the high-frequency input component as linear, and parametrising the coefficients of such linear system with respect to the low-frequency input component. We present a validation of the model against experiments, and show that the proposed LPV formulation captures the most relevant non-linearities involved in the DE speaker operation.