Improved Model for Conical Dielectric Elastomer Actuators With Fewer Electrical Connections

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Hector Medina ◽  
Carson W. Farmer
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Dielectric Elastomer ◽  
Artificial Muscles ◽  
Multiple Degrees Of Freedom ◽  
Dielectric Elastomer Actuators ◽  
Proposed Model ◽  
Robotic Joints ◽  
Improved Model ◽  
Electrical Connections

Abstract Dielectric elastomers (DEs) exhibit remarkable properties that make them stand out among other electroactive polymers. Various types of actuators based on DEs have been used in applications that include artificial muscles, Braille displays, and robotic joints. In particular, conical dielectric elastomer actuators (CDEAs) are very attractive due to their multiple degrees of freedom (DOF) and easiness of construction. In this study, an energy method is used to derive an improved mathematical model for a double-cone dielectric elastomer actuator (DCDEA) capable of predicting horizontal and rotational displacements. To create the model, a new variable is introduced into the equations, the azimuth angle. In addition, a new pattern of electrodes is proposed as a method for achieving five DOF using only half of the electrode connections of traditional DCDEAs. Experimental tests are carried out and used to validate the proposed model. Results show very close agreement. A limiting aspect of the proposed model is that it relies on two experimental correction coefficients. Nonetheless, the model derived provides a means to more accurately implement automatic control to robotic systems that use DCDEAs (work in progress).

scholarly journals Dielectric Elastomer Actuator Driven Soft Robotic Structures With Bioinspired Skeletal and Muscular Reinforcement

2020 ◽  
Vol 7 ◽  
Author(s):  
M. Franke ◽  
A. Ehrenhofer ◽  
S. Lahiri ◽  
E.-F. M. Henke ◽  
T. Wallmersperger ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Aerosol Deposition ◽  
Dielectric Elastomer ◽  
Artificial Muscles ◽  
Soft Systems ◽  
Natural Motion ◽  
Dielectric Elastomer Actuators ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Laminate Theory

Natural motion types found in skeletal and muscular systems of vertebrate animals inspire researchers to transfer this ability into engineered motion, which is highly desired in robotic systems. Dielectric elastomer actuators (DEAs) have shown promising capabilities as artificial muscles for driving such structures, as they are soft, lightweight, and can generate large strokes. For maximum performance, dielectric elastomer membranes need to be sufficiently pre-stretched. This fact is challenging, because it is difficult to integrate pre-stretched membranes into entirely soft systems, since the stored strain energy can significantly deform soft elements. Here, we present a soft robotic structure, possessing a bioinspired skeleton integrated into a soft body element, driven by an antagonistic pair of DEA artificial muscles, that enable the robot bending. In its equilibrium state, the setup maintains optimum isotropic pre-stretch. The robot itself has a length of 60 mm and is based on a flexible silicone body, possessing embedded transverse 3D printed struts. These rigid bone-like elements lead to an anisotropic bending stiffness, which only allows bending in one plane while maintaining the DEA's necessary pre-stretch in the other planes. The bones, therefore, define the degrees of freedom and stabilize the system. The DEAs are manufactured by aerosol deposition of a carbon-silicone-composite ink onto a stretchable membrane that is heat cured. Afterwards, the actuators are bonded to the top and bottom of the silicone body. The robotic structure shows large and defined bimorph bending curvature and operates in static as well as dynamic motion. Our experiments describe the influence of membrane pre-stretch and varied stiffness of the silicone body on the static and dynamic bending displacement, resonance frequencies and blocking forces. We also present an analytical model based on the Classical Laminate Theory for the identification of the main influencing parameters. Due to the simple design and processing, our new concept of a bioinspired DEA based robotic structure, with skeletal and muscular reinforcement, offers a wide range of robotic application.

Multiple-degrees-of-freedom dielectric elastomer actuators for soft printable hexapod robot

2017 ◽  
Vol 267 ◽  
pp. 505-516 ◽  
Author(s):  
Canh Toan Nguyen ◽  
Hoa Phung ◽  
Tien Dat Nguyen ◽  
Hosang Jung ◽  
Hyouk Ryeol Choi
Keyword(s):  
Degrees Of Freedom ◽  
Dielectric Elastomer ◽  
Hexapod Robot ◽  
Multiple Degrees Of Freedom ◽  
Dielectric Elastomer Actuators

scholarly journals Implementation of Soft-Lithography Techniques for Fabrication of Bio-Inspired Multi-Layer Dielectric Elastomer Actuators with Interdigitated Mechanically Compliant Electrodes

Actuators ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 73 ◽  
Author(s):  
Mert Corbaci ◽  
Wayne Walter ◽  
Kathleen Lamkin-Kennard
Keyword(s):  
Soft Lithography ◽  
Skeletal Muscles ◽  
Actuation Voltage ◽  
Transition Process ◽  
Humanoid Robots ◽  
Dielectric Elastomer ◽  
Industrial Robots ◽  
Artificial Muscles ◽  
Dielectric Elastomer Actuators ◽  
Soft Actuators

Advancements in software engineering have enabled the robotics industry to transition from the use of giant industrial robots to more friendly humanoid robots. Soft robotics is one of the key elements needed to advance the transition process by providing a safer way for robots to interact with the environment. Electroactive polymers (EAPs) are one of the best candidate materials for the next generation of soft robotic actuators and artificial muscles. Lightweight dielectric elastomer actuators (DEAs) provide optimal properties such as high elasticity, rapid response rates, mechanical robustness and compliance. However, for DEAs to become widely used as artificial muscles or soft actuators, there are current limitations, such as high actuation voltage requirements, control of actuation direction, and scaling, that need to be addressed. The authors’ approach to overcome the drawbacks of conventional DEAs is inspired by the natural skeletal muscles. Instead of fabricating a large DEA device, smaller sub-units can be fabricated and bundled together to form larger actuators, similar to the way myofibrils form myocytes in skeletal muscles. The current study presents a novel fabrication approach, utilizing soft lithography and other microfabrication techniques, to allow fabrication of multilayer stacked DEA structures, composed of hundreds of micro-sized DEA units.

Prediction of the Behavior of Dynamically Actuated DE Roll-Actuators Using Equivalent Circuits

2020 ◽  
Author(s):  
Petko Bakardjiev ◽  
Uwe Marschner ◽  
Markus Franke ◽  
Andreas Richter ◽  
Ercan M. Altinsoy
Keyword(s):  
Degrees Of Freedom ◽  
Model Updating ◽  
Experimental Studies ◽  
Axial Direction ◽  
Dielectric Elastomer ◽  
Design Parameters ◽  
Interface Circuits ◽  
Efficient Manner ◽  
Dielectric Elastomer Actuators ◽  
Conventional Systems

Abstract Dielectric elastomer actuators show suitable properties to be utilized for dynamic applications, e.g. speakers, shakers and pumps, with possible benefits to existing conventional systems. In this work a method to predict the performance of dynamically actuated dielectric-elastomer roll-actuators (DERA) depending on both, material and design parameters is presented. It incorporates in combination analytical computation, FEM, as well as electromechanical networks and considers a large variety of material configurations with a multitude of constructional degrees of freedom. DERA in push-configuration exhibit a distinct modal behavior in axial direction depending on the boundary conditions and loading at the actuators end terminals, which is described sufficiently by a one-dimensional longitudinal waveguide model. Several DERA were designed, manufactured and tested. The experimental studies were in good agreement with the made predictions. They allowed for further refinement regarding interface circuits and model updating, such as the estimation of inaccessible parameters (e. g. damping coefficients). The presented model allows for extensive parameter studies and the development of tailor-made actuators for given application in a very time efficient manner.

scholarly journals Modeling and System Integration for a Thin Pneumatic Rubber 3-DOF Actuator

Actuators ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 32 ◽  
Author(s):  
Shuhei Kawamura ◽  
Mizuki Sudani ◽  
Mingcong Deng ◽  
Yuichi Noge ◽  
Shuichi Wakimoto
Keyword(s):  
System Integration ◽  
Degrees Of Freedom ◽  
Small Diameter ◽  
Experimental System ◽  
Longitudinal Direction ◽  
Axial Direction ◽  
Artificial Muscles ◽  
Contraction Force ◽  
Proposed Model ◽  
Soft Actuators

Recently, soft actuators have been getting increased attention within various fields. The actuators are composed of flexible materials and driven by pneumatic pressure. A thin pneumatic rubber actuator generating 3 degrees of freedom motion, called 3-DOF micro-hand, has small diameter McKibben artificial muscles which generate a contraction force in the axial direction. By this structure, the micro-hand contracts in the longitudinal direction and bends in any direction by changing the applied air pressure pattern to the artificial muscles. The input–output relation of the micro-hand, however, is complicated and has not been modeled. In this paper, modeling for 3-DOF micro-hand is proposed. Moreover, the experimental system is built for the micro-hand and the proposed model is evaluated by using the experimental results.

scholarly journals Dielectric Elastomer Actuator for Soft Robotics Applications and Challenges

2020 ◽  
Vol 10 (2) ◽  
pp. 640 ◽  
Author(s):  
Jung-Hwan Youn ◽  
Seung Mo Jeong ◽  
Geonwoo Hwang ◽  
Hyunwoo Kim ◽  
Kyujin Hyeon ◽  
...  
Keyword(s):  
State Of The Art ◽  
Dielectric Elastomer ◽  
Artificial Muscles ◽  
Soft Robot ◽  
Optical Components ◽  
Dielectric Characteristics ◽  
Dielectric Elastomer Actuators ◽  
Potential Applications ◽  
Working Principle ◽  
Soft Actuators

This paper reviews state-of-the-art dielectric elastomer actuators (DEAs) and their future perspectives as soft actuators which have recently been considered as a key power generation component for soft robots. This paper begins with the introduction of the working principle of the dielectric elastomer actuators. Because the operation of DEA includes the physics of both mechanical viscoelastic properties and dielectric characteristics, we describe theoretical modeling methods for the DEA before introducing applications. In addition, the design of artificial muscles based on DEA is also introduced. This paper reviews four popular subjects for the application of DEA: soft robot hand, locomotion robots, wearable devices, and tunable optical components. Other potential applications and challenging issues are described in the conclusion.

Modeling and Actuation Performance Analysis of Conically-Shaped Dielectric Electroactive Polymer Actuator

2014 ◽  
Vol 633-634 ◽  
pp. 250-256
Author(s):  
Yin Long Zhu ◽  
Hong Pin Zhou ◽  
Hua Ming Wang
Keyword(s):  
Dielectric Elastomer ◽  
Force Output ◽  
Energy Potential ◽  
Principal Stresses ◽  
Dielectric Elastomer Actuator ◽  
Design And Optimization ◽  
Dielectric Elastomer Actuators ◽  
Proposed Model ◽  
Polymer Actuator ◽  
Potential Applications

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.

scholarly journals Dielectric Elastomer Grippers

2021 ◽  
Vol 10 (5) ◽  
pp. 33-36
Author(s):  
Mills Patel ◽  
Rudrax Khamar ◽  
Akshat Shah ◽  
Tej shah ◽  
Bhavik Soneji
Keyword(s):  
Mechanical Properties ◽  
Power Generation ◽  
State Of The Art ◽  
Artificial Muscle ◽  
Dielectric Elastomer ◽  
Soft Robotics ◽  
Artificial Muscles ◽  
Dielectric Elastomer Actuators ◽  
Working Principle ◽  
Soft Actuators

This paper appraisals state-of-the-art dielectric elastomer actuators (DEAs) and their forthcoming standpoints as soft actuators which have freshly been considered as a crucial power generation module for soft robots. DEs behave as yielding capacitors, expanding in area and attenuation in thickness when a voltage is applied. The paper initiates with the explanation of working principle of dielectric elastomer grippers. Here the operation of DEAs include both physics and mechanical properties with its characteristics, we have describe methods for modelling and its introductory application. In inclusion, the artificial muscle based on DEA concept is also formally presented. This paper also elaborates DEAs popular application such as- Soft Robotics, Robotics grippers and artificial muscles.

scholarly journals Soft Robotic Gripper Based on Multi-Layers of Dielectric Elastomer Actuators

2021 ◽  
Vol 33 (4) ◽  
pp. 968-974
Author(s):  
Witchuda Thongking ◽  
Ardi Wiranata ◽  
Ayato Minaminosono ◽  
Zebing Mao ◽  
Shingo Maeda ◽  
...  
Keyword(s):  
Response Time ◽  
Low Cost ◽  
Fast Response ◽  
Dielectric Elastomer ◽  
Heel Strike ◽  
Soft Robotics ◽  
Artificial Muscles ◽  
Light Weight ◽  
Dielectric Elastomer Actuators ◽  
The Relationship

Dielectric elastomer actuators (DEAs) are a promising technology for soft robotics. The use of DEAs has many advantages, including light weight, resilience, and fast response for its applications, such as grippers, artificial muscles, and heel strike generators. Grippers are commonly used as grasping devices. In this study, we focus on DEA applications and propose a technology to expand the applicability of a soft gripper. The advantages of gripper-based DEAs include light weight, fast response, and low cost. We fabricated soft grippers using multiple DEA layers. The grippers successfully held or gripped an object, and we investigated the response time of the grippers and their angle characteristics. We studied the relationship between the number of DEA layers and the performance of our grippers. Our experimental results show that the multi-layered DEAs have the potential to be strong grippers.

scholarly journals Linear-Quadratic Regulator for Control of Multi-Wall Carbon Nanotube/Polydimethylsiloxane Based Conical Dielectric Elastomer Actuators

Actuators ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 18
Author(s):  
Titus Mulembo ◽  
Waweru Njeri ◽  
Gakuji Nagai ◽  
Hirohisa Tamagawa ◽  
Keishi Naito ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Rise Time ◽  
Electromechanical Coupling ◽  
Linear Quadratic Regulator ◽  
Fast Response ◽  
Dielectric Elastomer ◽  
Soft Robotics ◽  
Artificial Muscles ◽  
Linear Quadratic ◽  
Dielectric Elastomer Actuators

Conventional rigid actuators, such as DC servo motors, face challenges in utilizing them in artificial muscles and soft robotics. Dielectric elastomer actuators (DEAs) overcome all these limitations, as they exhibit complex and fast motions, quietness, lightness, and softness. Recently, there has been much focus on studies of the DEAs material’s non-linearity, the non-linear electromechanical coupling, and viscoelastic behavior of VHB and silicone-based conical DEAs having compliant electrodes that are based on graphite powder and carbon grease. However, the mitigation of overshoot that arises from fast response conical DEAs made with solid electrodes has not received much research focus. In this paper, we fabricated a conical configuration of multi-walled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) based DEAs with a rise time of 10 ms, and 50% peak overshoot. We developed a full feedback state-based linear-quadratic regulator (LQR) having Luenberger observer to mitigate the DEAs overshoot in both the voltage ON and OFF instances. The cone DEA’s model was identified and a stable and well-fitting transfer function with a fit of 94% was obtained. Optimal parameters Q = 70,000, R = 0.1, and Q = 7000, R = 0.01 resulted in the DEA response having a rise time value of 20 ms with zero overshoot, in both simulations and experiments. The LQR approach can be useful for the control of fast response DEAs and this would expand the potential use of the DEAs as artificial muscles in soft robotics.

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