Toward the Design of Multi Asymmetric Surface Dielectric Barrier Discharge (ASDBD) Actuators

This paper investigates the electrical and mechanical behaviors of a single-ASDBD actuator and a two-ASDBD one supplied in sinusoidal mode（1-10 kHz）.The main objective of our research is to determine the optimum frequency values for the function of these actuators with a given power supply.For this purpose,we determine the electrical power density input to the actuators versus frequency through two methods：i） a semi-theoretical method,based on an impedance calculation,and ii） an experimental method,based on direct electrical measurements.These methods show that the addition of a second ASDBD changes the resonance frequency value of the actuator by moving it towards low frequencies.After characterizing the aerodynamic mobile layer structure induced by the single-ASDBD actuator,we analyze experimentally the mechanical response of a two-ASDBD actuator as a function of the inter-ASDBD distance.The experiments demonstrate that the induced electric wind velocity and the electro-mechanical yield of a twoASDBD actuator reach a maximum value for an optimum inter-ASDBD distance,which is a useful value for the design of highly efficient multi-ASDBD actuators.

Design and experiments of a small resonant inchworm piezoelectric robot

A small resonant inchworm piezoelectric robot with six driving feet which are set evenly along the circumference is proposed and tested.A bonded-type structure is adopted to realize a small size.The radial bending vibration mode and longitudinal vibration mode are excited at the same frequency.The superposition of these two vibration modes makes the driving feet produce elliptical motions.And the driving force can be generated by friction coupling between the driving foot and the operating plane.The structure of the robot is designed by finite element simulation.The geometric parameters are adjusted to make the resonant frequencies of the vibration modes as close as possible.The elliptical trajectories generated at the driving feet are discussed in detail.The vibration and motion characteristics of the prototype are tested,and the resonant frequencies of the radial bending mode and the longitudinal vibration mode are degenerated successfully.The optimal working frequency of the prototype is 21.5 kHz.The maximum speed of the prototype is 200 mm/s,and the displacement resolution is 0.71μm.The measured results show that the resonant inchworm piezoelectric robot can be used for fast and high-precision transportation in narrow space.

Toward broad optimal output bandwidth dielectric elastomer actuators

Dielectric elastomer actuators(DEAs)are one of the most promising soft actuation technologies owing to their relatively high power density and electromechanical efficiency enabled by a resonant actuation technique.However,existing DEA designs suffer from a very narrow optimal output bandwidth close to resonance and poor output control capability due to their fixed geometrical configurations.This condition greatly limits their applications in programmable actuation and broad-bandwidth applications.Accordingly,this work developed a novel resonance tunable DEA(RTDEA)design for broad-optimal-output actuation bandwidths that is enabled by an integration of a stiffness and voltage control strategy.This design features a broad resonant frequency adjustment from 84 to 126 Hz and independent tunings of its resonant amplitude and frequency.Parametric studies were conducted to illustrate the fundamental principles behind the resonance tuning strategy,and optimization was performed to maximize the tuning capability.Here,a resonance tuning control strategy is proposed to achieve accurate adjustments of the RTDEA’s resonance based on the stiffness and voltage control strategy.These resonance tunable soft actuators are envisioned to greatly expand DEAs’applications in,for instance,soft robotic locomotion,human–robot communication,and active vibrational control with demands of broad actuation bandwidths and high output performance.