Dynamic Response of Tubular Dielectric Elastomer Sensors and Actuators

This paper presents experimental and numerical modeling results for the dynamic response of a tubular dielectric elastomer sensor and actuator for the first time. Dielectric elastomers (DE) are soft polymer based smart materials that can be potentially employed in applications such as artificial muscles (prosthetics), compliant limbs and graspers for robots and aircrafts or aquatic vehicles. In our previous work, the quasi-static response of tubular DE sensors was studied [1]. Here, a theoretical model is developed to predict the dynamic response of tubular DE transducers. To this end, inertia effects are included in our previous static model which yields a system of partial differential equations. The dynamic response of the tubular DE is obtained by numerically solving the simplified PDEs using a finite difference scheme. The capacitance change induced by the dynamic deformation of the tubular DE is also calculated by a simple electrostatic model. Several tubular DE transducer samples (VHB 4905 and silicone) were fabricated and an experimental setup was developed to investigate the dynamic response by measuring capacitance and radial deformation. In the sensing experiments, a sweep of dynamic pressure profiles (0∼5Hz) are applied It is observed that silicone transducers have a larger dynamic sensing range. In the actuation experiments, the deformation of the silicone actuator is monitored while a voltage signal (4.5kV) is applied from 0∼30Hz. The silicone actuator shows a good actuation response while high voltage is applied. The comparison between numerical and experimental results for the DE transducers shows an overall error of 3%.