Identification of the Nonlinear Response of Ionic Polymer Actuators using the Volterra Series

Abstract

Ionic polymer transducers exhibit coupling between three physical domains: electrical, chemical, and mechanical. This coupling enables their use as both sensors and actuators. Because this phenomenon was only recently discovered, the fundamental mechanisms governing the actuation and sensing response are still open for debate. However, since ionic polymers are very compliant, low-voltage transducers have become an increasingly researched intelligent material. In this paper we aim to gain a better understanding of the physical mechanisms involved in the actuation response by studying the nonlinear harmonic distortion. The Volterra series was the chosen identification technique for its potential to extract information about the nonlinearities. Results show that the solvent appears to play a significant role in the actuation response, as evidenced by a changing distortion from different solvents.