Design and analysis of compliant electrostatic actuators for robotics

Abstract

In this work, two different types of electrostatic actuators (dielectric elastomer actuator and curved electrode actuator) are designed and analyzed. Dielectric elastomer actuators (DEA) are a type of electrostatic actuators that are known to achieve large displacements $O(10^3)$ m [1] at high operating speeds $O(10^3)$m $s^{-1}$ [2]. In this work, the approach of a distributed electrode array with fractal interconnects was investigated, where a single large electrode is divided into $N (N \in {5, 13, 25})$ number of small electrodes (fractals) connected by serpentine structured interconnections. The static and dynamic performance of the actuator is investigated through experiments. The curved electrode actuator is an electrostatic actuator and embraces flexible design architecture. The curved electrode actuator is capable of achieving large displacements $O (10^{-5})$m and sufficient forces $O (10^{-5})$ N at operating frequencies up to 10 kHz [3]. The dynamics of the curved electrode actuator in viscous media have not been thoroughly investigated previously. In this work, a reduced order model is derived to study the performance of the actuator is studied over a broad range, three orders of magnitude of viscosity $C \in$ ∈[1,200], three orders of magnitude of permittivity $\varepsilon_f \in$ ∈[1,100], four orders of magnitude of input frequency $f \in$ [1,16384]Hz. Furthermore, the reduced order model derived to study the static and dynamic performance of the curved electrode actuator is advanced to study the contact dynamics of the actuator.