Compliant actuation based on dielectric elastomers for a force-feedback device: modeling and experimental evaluation

• Published in: Frattura ed integritá strutturale 2013-01, Vol.7 (23), p.47-56
• Main Authors: Vertechy, R., Bergamasco, M., Berselli, G., Parenti Castelli, V., Vassura, G.
• Format: Article
• Language: English
• Subjects: Biomechanics; Dielectric elastomers; Engineering; Feedback; Materials science
• ISSN: 1971-8993; 1971-8993
• DOI: 10.3221/IGF-ESIS.23.05

Thanks to their large power densities, low costs and shock-insensitivity, Dielectric Elastomers (DE)seem to be a promising technology for the implementation of light and compact force-feedback devices such as,for instance, haptic interfaces. Nonetheless, the development of these kinds of DE-based systems is not trivialowing to the relevant dissipative phenomena that affect the DE when subjected to rapidly changingdeformations. In this context, the present paper addresses the development of a force feedback controller foran agonist-antagonist linear actuator composed of a couple of conically-shaped DE films and a compliantmechanism behaving as a negative-rate bias spring. The actuator is firstly modeled accounting for the viscohyperelasticnature of the DE material. The model is then linearized and employed for the design of a forcecontroller. The controller employs a position sensor, which determines the actuator configuration, and a forcesensor, which measures the interaction force that the actuator exchanges with the environment. In addition, anoptimum full-state observer is also implemented, which enables both accurate estimation of the time-dependentbehavior of the elastomeric material and adequate suppression of the sensor measurement noise. Preliminaryexperimental results are provided to validate the proposed actuator-controller architecture