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

Abstract

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 trivial owing to the relevant dissipative phenomena that affect the DE when subjected to rapidly changing deformations. In this context, the present paper addresses the development of a force feedback controller for an agonist-antagonist linear actuator composed of a couple of conically-shaped DE films and a compliant mechanism behaving as a negative-rate bias spring. The actuator is firstly modeled accounting for the viscohyperelastic nature of the DE material. The model is then linearized and employed for the design of a force controller. The controller employs a position sensor, which determines the actuator configuration, and a force sensor, which measures the interaction force that the actuator exchanges with the environment. In addition, an optimum full-state observer is also implemented, which enables both accurate estimation of the time-dependent behavior of the elastomeric material and adequate suppression of the sensor measurement noise. Preliminary experimental results are provided to validate the proposed actuator-controller architecture.

A method to increase the dynamic deformation of a dielectric elastomer minimum energy structures rotary joint without increase of the voltage amplitude

“…Dielectric elastomers (DEs) have been considered to be the best candidate for artificial muscle-like actuators because of their high strain response (Brochu and Pei, 2010;Pelrine et al, 2000;Zhao and Suo, 2010), high energy densities (Wingert et al, 2006) that are 70 times higher than conventional electromagnetic actuators, and high energy conversion efficiencies (Karpelson et al, 2008;60%-90%). DEs have therefore attracted much attention to its use in artificial muscles (Anderson et al, 2011;O'Brien et al, 2012), soft robots (Jung et al, 2007;Zhao et al, 2014), tunable lenses (Carpi et al, 2011;Shian et al, 2013), force feedback controllers (Vertechy et al, 2013), pneumatic valves (Giousouf and Kovacs, 2013), and energy harvesting devices (Lv et al, 2015).…”

Robust control of dielectric elastomer diaphragm actuator for human pulse signal tracking

“…The unique features of DE material make it possible to use them in different fields. For robotics research purposes, with an additional supporting frame and mechanical components, diamond-shape and bow-tie-shape actuators were created [18][19][20], which are more suitable for practical purposes. In most of the applications of using DE material as actuator, the control system design is critical to achieve satisfactory positioning and tracking performances.…”