A Co-Axial Dielectric Elastomer Actuator

2008 ◽  
Vol 61 ◽  
pp. 81-84 ◽  
Author(s):  
Hristiyan Stoyanov ◽  
Guggi Kofod ◽  
Reimund Gerhard

Dielectric elastomer actuators based on Maxwell-stress induced deformation, are considered for many potential applications where high actuation strain and high energy density are required. They usually rely on a planar actuator configuration, however, a string-like actuator would be less bulky, and more versatile for several applications. In this paper, a co-axial dielectric elastomer actuator that produces relatively high actuation strain is presented. The actuator is manufactured through alternating dip-coating steps with insulating and conductive thin layers. A soluble thermoplastic block-copolymer, SEBS(poly-(styrene-ethylene-butylene-styrene), is used for the dielectric layers as well as for the host material of the compliant electrodes. Electrical conductivity of the electrodes is achieved by incorporation of conductive carbon-black particles in the elastomer matrix. Actuators with a single and with multiple active layers (up to three) have been successfully demonstrated. This geometry is advantageous in that it is compact and can be bundled easily, and should therefore be practical in applications such as “artificial muscles”.

2014 ◽  
Vol 633-634 ◽  
pp. 250-256
Author(s):  
Yin Long Zhu ◽  
Hong Pin Zhou ◽  
Hua Ming Wang

Dielectric elastomer actuators (DEAs) represent one class of electroactive polymers that have already demonstrated excellent performances and show potential applications in many fields. In this paper, we present a simplified conically-shaped dielectric elastomer actuator model to explore the effects of various preloads and actuation voltages on both the actuation displacement and force output of DEA. The strain energy potential of Yeoh is used and the viscoelasticity is also taken into account. Using the developed model, the numerical results of DEA including the actuation displacement, the distribution of the principal stretch ratios and principal stresses in the membrane and the force output can be obtained. With different preloads and actuation voltages, the actuation characteristic of conically-shaped dielectric elastomer actuator is explored experimentally and validates the results determined from the proposed model. The proposed model can be used for the design and optimization of conically-shaped dielectric elastomer actuator.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Li-Juan Yin ◽  
Yu Zhao ◽  
Jing Zhu ◽  
Minhao Yang ◽  
Huichan Zhao ◽  
...  

AbstractDielectric elastomer actuators (DEAs) with large electrically-actuated strain can build light-weight and flexible non-magnetic motors. However, dielectric elastomers commonly used in the field of soft actuation suffer from high stiffness, low strength, and high driving field, severely limiting the DEA’s actuating performance. Here we design a new polyacrylate dielectric elastomer with optimized crosslinking network by rationally employing the difunctional macromolecular crosslinking agent. The proposed elastomer simultaneously possesses desirable modulus (~0.073 MPa), high toughness (elongation ~2400%), low mechanical loss (tan δm = 0.21@1 Hz, 20 °C), and satisfactory dielectric properties ($${\varepsilon }_{{{{{{\rm{r}}}}}}}$$ ε r  = 5.75, tan δe = 0.0019 @1 kHz), and accordingly, large actuation strain (118% @ 70 MV m−1), high energy density (0.24 MJ m−3 @ 70 MV m−1), and rapid response (bandwidth above 100 Hz). Compared with VHBTM 4910, the non-magnetic motor made of our elastomer presents 15 times higher rotation speed. These findings offer a strategy to fabricate high-performance dielectric elastomers for soft actuators.


Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 69
Author(s):  
Julian Kunze ◽  
Johannes Prechtl ◽  
Daniel Bruch ◽  
Bettina Fasolt ◽  
Sophie Nalbach ◽  
...  

In this work, we develop a coreless rolled dielectric elastomer actuator (CORDEA) to be used as artificial muscles in soft robotic structures. The new CORDEA concept is based on a 50 µm silicone film with screen-printed electrodes made of carbon black suspended in polydimethylsiloxane. Two printed silicone films are stacked together and then tightly rolled in a spiral-like structure. Readily available off-the-shelf components are used to implement both electrical and mechanical contacts. A novel manufacturing process is developed to enable the production of rolled actuators without a hollow core, with a focus on simplicity and reliability. In this way, actuator systems with high energy density can be effectively achieved. After presenting the design, an experimental evaluation of the CORDEA electromechanical behavior is performed. Finally, actuator experiments in which the CORDEA is pre-loaded with a mass load and subsequently subject to cycling voltage are illustrated, and the resulting performance is discussed.


2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Lei Qin ◽  
Jiawei Cao ◽  
Yucheng Tang ◽  
Jian Zhu

Dielectric elastomer actuators (DEAs) exhibit interesting muscle-like attributes including large voltage-induced deformation and high energy density, thus can function as artificial muscles for soft robots/devices. This paper focuses on soft planar DEAs, which have extensive applications such as artificial muscles for jaw movement, stretchers for cell mechanotransduction, and vibration shakers for tactile feedback, etc. Specifically, we develop a soft planar DEA, in which compression springs are employed to make the entire structure freestanding. This soft freestanding actuator can achieve both linear actuation and turning without increasing the size, weight, or structural complexity, which makes the actuator suitable for driving a soft crawling robot. Furthermore, its simple structure and homogeneous deformation allow for analytic modeling, which can be used to interpret the large voltage-induced deformation and interesting mechanics phenomenon (i.e., wrinkling and electromechanical instability). A preliminary demonstration showcases that this soft planar actuator can be employed as an artificial muscle to drive a soft crawling robot.


Author(s):  
Johannes Prechtl ◽  
Julian Kunze ◽  
Giacomo Moretti ◽  
Daniel Bruch ◽  
Stefan Seelecke ◽  
...  

Abstract Due to their large deformation, high energy density, and high compliance, dielectric elastomer actuators (DEAs) have found a number of applications in several areas of mechatronics and robotics. Among the many types of DEAs proposed in the literature, rolled DEAs (RDEAs) represent one of the most popular configurations. RDEAs can be effectively used as compact muscle-like actuators for soft robots, since they allow eliminating the need for external motors or compressors while providing at the same time a flexible and lightweight structure with self-sensing capabilities. To effectively design and control complex RDEA-driven systems and robots, accurate and numerically efficient mathematical models need to be developed. In this work, we propose a novel lumped-parameter model for silicone-based, thin and tightly rolled DEAs. The model is grounded on a free-energy approach, and permits to describe the electro-mechanically coupled response of the transducer with a set of nonlinear ordinary differential equations. After deriving the constitutive relationships, the model is validated by means of an extensive experimental campaign, conducted on three RDEA specimens having different geometries. It is shown how the developed model permits to accurately predict the effects of several parameters (external load, applied voltage, actuator geometry) on the RDEA electro-mechanical response, while maintaining an overall simple mathematical structure.


2022 ◽  
Vol 429 ◽  
pp. 132258
Author(s):  
Wenpeng Zang ◽  
Xueying Liu ◽  
Junjie Li ◽  
Yingjie Jiang ◽  
Bing Yu ◽  
...  

Soft Matter ◽  
2017 ◽  
Vol 13 (37) ◽  
pp. 6390-6395 ◽  
Author(s):  
Ye Rim Lee ◽  
Hyungho Kwon ◽  
Do Hoon Lee ◽  
Byung Yang Lee

Electrodes consisting of silver nanowires and carbon nanotubes enable a dielectric elastomer actuator to become highly stretchable and optically transparent.


2018 ◽  
Vol 29 (11) ◽  
pp. 2424-2436 ◽  
Author(s):  
Yanping Tian ◽  
Yong Wang ◽  
Xiaoling Jin ◽  
Zhilong Huang

Dielectric elastomer actuators have gained extensive attention in scientific and industrial communities with the rapid development of soft robot technology. There still remain some questions on the control aspect of nonlinear system with dielectric elastomer actuator. The first is whether the soft actuator can successfully drive the primary structure to track an arbitrary prescribed trajectory. The second is how to suppress the random vibration around the equilibrium position when the primary structure is disturbed by external excitation. This article seeks the answers for these two questions. By directly solving the governing equation of motion, an open-loop control technique is designed to track a prescribed trajectory. The effectiveness of the trajectory tracking technique is investigated and the limitation is illustrated by the influence of inertia of the primary structure. Based on the stochastic averaging of energy envelope and stochastic dynamic programming principle, a clipped control strategy is proposed by slightly adjusting the voltage in real time to suppress the random vibration around the equilibrium position. The good effectiveness and high robustness of the clipped control strategy are verified numerically. This work may provide some guidelines for the control aspect of nonlinear systems with dielectric elastomer actuators.


2021 ◽  
Author(s):  
Yucai Li ◽  
Yan Zhao ◽  
Shiwei Song ◽  
Jian wang

Abstract Core-shell structured NiCo2S4@NiMoO4 is considered to be one of the most promising electrode materials for supercapacitors due to its high specific capacitance and excellent cycle performance. In this work, we report NiCo2S4@NiMoO4 nanosheets on Ni foam by two-step fabricated method. The as-obtained product has high capacitance of 1102.5 F g− 1 at 1 A g− 1. The as-assembled supercapacitor has also a high energy density of 37.6 W h kg− 1 and superior cycle performance with 85% capacitance retention. The electrode materials reported here might exhibits potential applications in future energy storage devices.


Author(s):  
Heather Lai ◽  
Chin An Tan ◽  
Yong Xu

Human walking requires sophisticated coordination of muscles, tendons, and ligaments working together to provide a constantly changing combination of force, stiffness and damping. In particular, the human knee joint acts as a variable damper, dissipating greater amounts of energy when the knee undergoes large rotational displacements during walking, running or hopping. Typically, this damping results from the dissipation, or loss, of metabolic energy. It has been proven to be possible however; to collect this otherwise wasted energy through the use of electromechanical transducers of several different types which convert mechanical energy to electrical energy. When properly controlled, this type of device not only provides desirable structural damping effects, but the energy generated can be stored for use in a wide range of applications. A novel approach to an energy harvesting knee joint damper is presented using a dielectric elastomer (DE) smart material based electromechanical transducer. Dielectric elastomers are extremely elastic materials with high electrical permittivity which operate based on electrostatic effects. By placing compliant electrodes on either side of a dielectric elastomer film, a specialized capacitor is created, which couples mechanical and electrical energy using induced electrostatic stresses. Dielectric elastomer energy harvesting devices not only have a high energy density, but the material properties are similar to that of human tissue, making it highly suitable for wearable applications. A theoretical framework for dielectric elastomer energy harvesting is presented along with a mapping of the active phases of the energy harvesting to the appropriate phases of the walking stride. Experimental results demonstrating the energy harvesting capability of a DE generator undergoing strains similar to those experienced during walking are provided for the purpose of verifying the theoretical results. The work presented here can be applied to devices for use in rehabilitation of patients with muscular dysfunction and transfemoral prosthesis as well as energy generation for able-bodied wearers.


Sign in / Sign up

Export Citation Format

Share Document