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 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

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).

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Workspace, dexterity and dimensional optimization of microhexapod

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Screw Theory ◽  
Design Parameters ◽  
Dimensional Synthesis ◽  
Content Type ◽  
Workspace Analysis ◽  
The Difference ◽  
Flexure Joints ◽  
6 Degrees Of Freedom

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.

Sign in / Sign up

Export Citation Format

Share Document