scholarly journals Flexible Vibrotactile Actuator Based on Dielectric Elastomer for Smart Handheld Devices

2021 ◽  
Vol 11 (24) ◽  
pp. 12020
Author(s):  
Yong Hae Heo ◽  
Dong-Soo Choi ◽  
Do Eun Kim ◽  
Sang-Youn Kim
Keyword(s):  
Applied Voltage ◽  
Dielectric Layer ◽  
Lower Layer ◽  
Electrostatic Force ◽  
Weight Ratio ◽  
Dielectric Elastomer ◽  
Wide Frequency Range ◽  
Handheld Devices ◽  
Adhesive Tape ◽  
Initial State

This paper presents an electroactive and soft vibrotactile actuator based on a dielectric elastomer. The vibrotactile actuator is composed of an upper layer, an adhesive tape layer, a dielectric layer with bumps, and a lower layer. When a voltage is applied to the actuator, an electrostatic force created between the upper and lower layers pulls the upper layer down, compressing the dielectric layer. As soon as the applied voltage is released, the upper layer is quickly restored to its initial state by the elastic force of the compressed dielectric elastomer. Because two forces contribute to the actuation at the same time, the created vibration is sufficiently strong to stimulate human mechanoreceptors. When the applied voltage is removed, the upper layer and dielectric elastomer return to their initial shapes. We conducted experiments to determine the best weight ratio of polydimethylsiloxane (PDMS) and Ecoflex, and to quantitatively investigate the haptic performance of the proposed vibrotactile actuator. The experiments clearly show that the plasticized vibrotactile actuator can create a variety of haptic sensations over a wide frequency range.

Isometric Stress Analysis and Current-Voltage Characteristics of Some Nanoclay Dielectric Elastomer Compounds

2007 ◽  
Author(s):  
N. Nurminen ◽  
A. Ellman ◽  
V. Jouppila ◽  
M. Paajanen ◽  
M. Karesoja
Keyword(s):  
Material Model ◽  
Dielectric Elastomer ◽  
Adhesive Tape ◽  
Electromechanical Properties ◽  
Dependent Behavior ◽  
Current Voltage ◽  
New Type ◽  
Current Voltage Characteristics ◽  
Compound Materials ◽  
Different Levels

The electromechanical properties of elastomer material change when different levels of stretching are applied to the elastomer film. The generated stress and expansion of the EAP material depend on the electric field across the material and its relative permeability. Some of the best known commercial dielectric elastomer materials are based on acrylic elastomers, e.g. 3M VHB 4910 or 4905 adhesive tape. In this work, the VHB 4910 tape was used as a reference material for different types of acrylic nanoclay compound materials. These new type of nanoclay elastomer compounds were tested because the addition of clay into the elastomer was assumed to increase its actuating performance. Different voltage and pre-stretching levels were used in the measurements. Current-voltage characteristics and isometric stress measurements were used to study the energy efficiency, frequency dependent behavior, reactivity and isometric stress performance of the EAP materials. Based on the electromechanical characterization and material properties, a general hyperelastic material model was developed. According to the preliminary tests, the nanoclay compound seems to be a bit stiffer than VHB 4910 resulting in a greater isometric stress response.

scholarly journals Microstructural dielectric elastomer actuator with uniaxial in-plane contraction

2012 ◽  
Vol 24 (3) ◽  
pp. 347-356 ◽  
Author(s):  
Shih-Chieh Lin ◽  
Wen-Pin Shih ◽  
Pen-Zen Chang
Keyword(s):  
Bias Voltage ◽  
Electrostatic Force ◽  
Dielectric Elastomer ◽  
Dielectric Elastomer Actuator

A micromachined dielectric elastomer actuator with uniaxial in-plane contraction was proposed. The modeling, fabrication, and testing of the actuator were carried out. When a bias voltage was applied, the resulting electrostatic force compressed the dielectric elastomer that then shrank in area due to its embedded microstructures. The proposed dielectric elastomer actuator consisted of two electrode layers, two flexible layers, and a microstructural layer. The microstructural layer possessed the grating patterns that served as the spacers to define the gap between the top and bottom flexible layers. The grating patterns also determined the direction of the in-plane contraction. When the applied electrostatic force pulled together the bottom and top flexible layers, these two layers bent inwardly and shortened the distance between the spacers. The design of the bending actuation was demonstrated utilizing the asymmetric thickness design of the flexible layers.

Dynamic Actuation of Electro-Elastic Spherical Membranes Using Dielectric Elastomers

Aerospace ◽  
2005 ◽  
Author(s):  
Nakhiah Goulbourne ◽  
Eric Mockensturm ◽  
Mary Frecker
Keyword(s):  
Dynamic Response ◽  
Applied Voltage ◽  
Gas Flow ◽  
Applied Pressure ◽  
Material Model ◽  
Dielectric Elastomer ◽  
Inertial Effects ◽  
Mechanical Pressure ◽  
Material Parameters ◽  
Dielectric Elastomer Actuators

This paper presents dynamic results for spherical dielectric elastomer actuators subject to an inflating mechanical pressure and an applied voltage. Different equilibria modes arise during dynamic operation due to inertial effects. In previous work, the inertial effects have been studied for the limited case of a constant applied pressure during membrane deformation [1]. Here, novel results are presented in which the dynamic response of spherical dielectric elastomer actuators to a pressure-time loading history as well as a more realistic constant gas flow rate are considered. The results are calculated for both the damped and the zero-damped cases. The spherical membrane is assumed to follow the Mooney material model where various inflation modes arise depending on the material parameters. The range of Mooney material parameters considered, the driving pressure and the applied voltage all affect the dynamic response.

Design and Analysis of Hemispherical Electrostatic Micro Deformable Focusing Mirror

Volume 3 ◽  
2004 ◽  
Author(s):  
Shang-Wei Tsai ◽  
Meng-Ju Lin
Keyword(s):  
Applied Voltage ◽  
Electrostatic Force ◽  
Focal Length ◽  
Length Change ◽  
Least Square ◽  
Limit Values ◽  
Etching Depth ◽  
Isotropic Etching ◽  
Length Changes ◽  
Structure Layer

For uniform deformation, based on bulk microfabrication with isotropic etching, two types of hemispherical electrostatic micro deformable focusing mirror are designed. One of the focusing mirrors is center-anchored, and the other is circular clamped. Using theory of shells, theoretical solution of deformation under uniform electrostatic force is derived. For more detail analysis of the electrostatic and elastic forces coupling problem, finite element is used to analyze the deformation of the mirror structure. Applying electrostatic force, the profile of micro focusing mirror will be not the spherical and change to become a curve like parabolic surface. Using least square method, the curve is fitted as a parabolic curve and the focal lengths of the focusing micro mirror are obtained. The result shows the focal length without applying electrostatic force can be determined by different micro mirror radius and isotropic etching depth. When the electrostatic forces are applied, the deformation and the focal length change differently between the two types of focusing mirror. For circular clamped micro mirror, the deformation is larger near circular clamped region and uniform in the center regime. Therefore, the relation of focal length and applying voltage is a concave curve with minimum values. That is, the focusing length decreasing as the applying voltage increasing and reaches a limit values. When the applying voltage continues increasing after reaching the minimum value, the focal length increases fast. It also shows the thicker structure layer needs larger applied voltage. But the focal length changes in larger stroke. The pull-in voltage is about 100 volt when the structure layer are both 2 μm. However, the pull-in voltage increases nonlinearly as gap increasing. When the gap increases to 4 μm, the pull-in voltage is about 300 volt. The result shows center-anchored micro mirror has better performance. The deformation is more uniform and the focal length increases nonlinearly as applied voltage increasing. It is found the stroke of focal length is larger and the applied voltage is less. The results shows even when the gap and structure layer is 4 and 2 μm, the pull-in voltage is about 62 volts. However, the stoke changes from 990 to about 1320 μm when applying voltage is from 0 to 60 volts. Therefore, with low applied voltage and large focal length stoke, the center-anchored micro mirror has good performance.

A Novel Bi-Stable Force Sensor: Theory and Modeling

2009 ◽  
Author(s):  
Pezhman A. Hassanpour ◽  
Patricia M. Nieva ◽  
Amir Khajepour
Keyword(s):  
Analytical Model ◽  
Axial Force ◽  
Applied Voltage ◽  
Electrostatic Force ◽  
Force Sensor ◽  
Time Response ◽  
Constant Rate ◽  
New Type ◽  
Linear And Nonlinear ◽  
Theory And Modeling

In this paper, a novel sensing mechanism is introduced. This mechanism consists of a clamped-clamped beam and two parallel electrodes. An analytical model of the system, that takes into account the mechanical linear and nonlinear stiffnesses as well as the nonlinear electrostatic force, is developed. The time response of the system to a disturbance is derived while the applied voltage is increasing at a constant rate. It has been shown that the voltage, that destabilize the beam, can be used as a measure of the axial force in the beam. This technique can be used in the development of new type of sensors.

The Electromechanical Behavior of Dielectric Elastomer Actuator Stiffened by Fiber

2018 ◽  
Vol 765 ◽  
pp. 12-15 ◽  
Author(s):  
Long Zhou Lyu ◽  
Shi Jie Zhu
Keyword(s):  
Applied Voltage ◽  
Applied Load ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Dielectric Elastomer ◽  
Functional Material ◽  
Dielectric Elastomer Actuator ◽  
Electromechanical Behavior ◽  
Electromechanical Performance

Dielectric elastomer is functional material that can convert electrical energy to mechanical energy. In this paper, a cylindrical dielectric elastomer actuator was designed and fabricated by using fiber stiffening to improve its electromechanical performance. the effects of pre-straining, rate of applied voltage and fiber stiffening on the electromechanical behavior were investigated by the experiments. It was found that the best applied load for pre-straining was 524g based on the electromechanical tests at the applied voltage rate of 10V/s. The maximum actuated strain decreased with an increase in rate of applied voltage. When the fibers were embedded in the dielectric elastomer actuator, the maximum actuated strain was 27.5%, doubled the value of 14% without fiber stiffening at the applied voltage rate of 20V/s.

An Actuator for Controlling the Area of Dielectric Layer of the Tunable Capacitor by Commercial CMOS Fabrication

2003 ◽  
Author(s):  
Jing-Hung Chiou ◽  
Ran-Jin Lin ◽  
Ching-Liang Dai ◽  
Kai-Hsiang Yen ◽  
Yu-Ching Shih ◽  
...  
Keyword(s):  
Cantilever Beam ◽  
Dielectric Layer ◽  
Electrostatic Force ◽  
Complementary Metal Oxide Semiconductor ◽  
Beam Width ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Fixed Plate ◽  
Tunable Capacitor ◽  
Post Process

This study describes the fabrication of an actuator of controlling the area of a dielectric layer using the commercial 0.35μm Single Polysilicon Four Metals (SPFM) Complementary Metal Oxide Semiconductor (CMOS) process and a post-process. The post-process requires wet and dry etching without using a mask to etch sacrificial layers and release the structures suspended in the actuator. The actuator is composed of a top suspended plate, a bottom fixed plate, and a laterally yielding cantilever beam, and two fixed curved electrodes. One end of the cantilever beam is anchored whereas the other end is connected to the suspended plate. The fixed curved electrodes and the cantilever beam are stacked layers of metals and via layers, formed by the CMOS process. The cantilever beam is deflected over a large distance using electrostatic force and the suspended plate swings laterally to increase or decrease the area of overlap between itself and the bottom fixed plate. The dimensions of the actuator are: suspended plate diameter = 100 μm; cantilever beam width = 2 μm, height = 6 μm, and length = 300 μm. The moved end of the cantilever beam, connected to the suspended plate, is deflected by 25 μm when a dc power supply of 60V is applied to it.

Vibrational Characteristics of Micro Beams

2005 ◽  
Author(s):  
Oladipo Onipede ◽  
Ilya Avdeev ◽  
Amir Khalilollahi ◽  
Lisa Buziewicz
Keyword(s):  
Natural Frequency ◽  
Applied Voltage ◽  
Dynamic Properties ◽  
Electrostatic Force ◽  
Elastic Stiffness ◽  
Critical Parameters ◽  
Driving Voltage ◽  
Mems Devices ◽  
Non Linear ◽  
Voltage Frequency

Several high frequency MEMS devices such as resonators and filters can be modeled as electrostatically driven micro-beams. While their static structural response depends solely on the magnitude of the applied voltage and their elastic stiffness, their dynamic response also depends on their mass, damping properties and the applied voltage frequency. In designing these devices, critical parameters must include the maximum voltage, voltage frequency and the natural frequency of the system. Even though the electrostatic force developed by the voltage is non-linear, the system can be modeled as a harmonic system due to the periodic nature of the response. Results from a non-linear structural-electrostatic dynamic model show the importance of the dynamic properties and the non-linear electrostatic force. The results show significantly lower limiting voltages, especially when the driving voltage is close to the natural frequency of the system. The effect of damping is also addressed.

scholarly journals Barium titanate flakes based composites for microwave absorbing applications

2013 ◽  
Vol 7 (4) ◽  
pp. 189-193 ◽  
Author(s):  
Raj Jain ◽  
Ashish Dubey ◽  
Amit Soni ◽  
Sanjiv Gupta ◽  
Trilok Shami
Keyword(s):  
Barium Titanate ◽  
Reflection Loss ◽  
Composite Laminates ◽  
Sol Gel ◽  
Tape Casting ◽  
Weight Ratio ◽  
Single Layer ◽  
Wide Frequency Range ◽  
Nano Particles ◽  
Electromagnetic Properties

Barium titanate (BT) has attained research focus in recent past owing to considering its high dielectric constant and stealth capabilities in microwave region. Shape effects of BT viz. powder, micron size flakes, nano particles and nanotubes have been studied vastly for its stealth capabilities. Present study aims at the preparation of millimetric size barium titanate flakes (BTFs) via controlled sol-gel process followed by tape casting. BTFs were mixed in varied weight ratio (50-90 wt.%) with polyurethane resin to fabricate composite laminates. Electromagnetic properties measurement in X and Ku band revealed high values of real and imaginary permittivity. Reflection loss measurements demonstrated more than 20 dB loss in wide frequency range (11.4-13.6 GHz). For single layer microwave absorber, reflection loss values have been calculated and it is observed that calculated and measured reflection loss values are in good agreement to each other. Developed material can find applications in broadband radar signature reduction.

scholarly journals Miniaturized Coupling Structures for Decoupling PIFAs on Handheld Devices

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Qian Li ◽  
Yaxin Yu
Keyword(s):  
Electromagnetic Field ◽  
Correlation Coefficient ◽  
Dielectric Layer ◽  
Mutual Coupling ◽  
Ground Plane ◽  
Measured Data ◽  
Handheld Devices ◽  
Handheld Device ◽  
Small Spacing ◽  
Thin Dielectric Layer

One efficient approach is introduced in this paper to reduce mutual coupling and correlation coefficient for two closely placed PIFAs in a handheld device. The approach is based on one miniaturized structure which consists of two metallic layers, printed on either side of one thin dielectric layer. Due to the small spacing between two conducting patches, high electromagnetic field is induced within the dielectric layer. The geometry and position of this structure have been modified to decouple the PIFA array at 1.9 GHz and produce maximum miniaturization thereby occupying less space on a handheld device ground plane. By employing the proposed structures, a 20 dB reduction in mutual coupling is achieved. The correlation coefficient also reduces to 0.007278. The performance of the structure is validated by both simulated results and measured data obtained from several fabricated prototypes.

Sign in / Sign up

Export Citation Format

Share Document