Novel Dielectric Elastomer Actuator Configurations and Devices for Soft Robotic and Wearable Applications
Novel Dielectric Elastomer Actuator Configurations and Devices for Soft Robotic and Wearable Applications

Author: Roshan Joseph Plamthottam

Publisher:

Published: 2023

Total Pages: 0

ISBN-13:

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Soft robotic devices require highly stretchable and flexible materials to ensure that they can conform to delicate objects and work safely alongside humans. As a result, new flexible actuation technologies must be developed so that soft robotic platforms can achieve their desired function. Dielectric elastomer actuators are an emerging actuator technology that possesses high energy density in a lightweight package. However, since these actuators utilize a thin, soft elastomer film, they are particularly delicate and depending on their configuration, do not efficiently outcouple their outputted mechanical energy. Rigid frames, metallic springs, and other mechanisms have been used in the past to improve the performance of these actuators in various configurations, but these highly stiff components are not ideal for soft robotic applications. Novel strategies can be implemented to mitigate these issues. In this work, we highlight new strategies to create novel dielectric elastomer actuator configurations with high power density, large strokes, and high force output. First, we discuss the development of a core-free rolled dielectric elastomer. We then discuss a flexible DEA-based fluidic pump that can output high flowrates and withstand large pressures for its small size. Finally, we detail a novel mechanism to control the deformation direction of DEAs, and leverage this mechanism to create a patch-like haptic interface for virtual reality applications.

Large Deformable Soft Actuators Using Dielectric Elastomer and Origami Inspired Structures
Large Deformable Soft Actuators Using Dielectric Elastomer and Origami Inspired Structures

Author: JangHo Park

Publisher:

Published: 2019

Total Pages: 254

ISBN-13:

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"There have been significant developments in the field of robotics. Significant development consists of new configurations, control mechanisms, and actuators based upon its applications. Despite significant improvements in modern robotics, the biologically inspired robots has taken the center stage. Inspired by nature, biologically inspired robots are called ‘soft robots’. Within these robots lies a secret ingredient: the actuator. Soft robotic development has been driven by the idea of developing actuators that are like human muscle and are known as ‘artificial muscle’. Among different materials suitable for the development of artificial muscle, the dielectric elastomer actuator (DEA) is capable of large deformation by applying an electric field. Theoretical formulation for DEA was performed based upon the constitutive hyperelastic models and was validated by using finite element method (FEM) using ABAQUS. For FEM, multistep analysis was performed to apply pre-stretch to the membrane before applying actuation voltage. Based on the validation of DEA, different configurations of DEA were investigated. Helical dielectric elastomer actuator and origami dielectric elastomer actuator were investigated using theoretical modeling. Comparisons were made with FEM to validate the model. This study focus on the theoretical and FEM analysis of strain within the different configuration of DEA and how the actuation strain of the dielectric elastomer can be translated into contraction and/or bending of the actuator."--Abstract.

Soft Robotics in Rehabilitation
Soft Robotics in Rehabilitation

Author: Amir Jafari

Publisher: Academic Press

Published: 2021-02-20

Total Pages: 280

ISBN-13: 0128185392

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Soft Robotics in Rehabilitation explores the specific branch of robotics dealing with developing robots from compliant and flexible materials. Unlike robots built from rigid materials, soft robots behave the way in which living organs move and adapt to their surroundings and allow for increased flexibility and adaptability for the user. This book is a comprehensive reference discussing the application of soft robotics for rehabilitation of upper and lower extremities separated by various limbs. The book examines various techniques applied in soft robotics, including the development of soft actuators, rigid actuators with soft behavior, intrinsically soft actuators, and soft sensors. This book is perfect for graduate students, researchers, and professional engineers in robotics, control, mechanical, and electrical engineering who are interested in soft robotics, artificial intelligence, rehabilitation therapy, and medical and rehabilitation device design and manufacturing. Outlines the application of soft robotic techniques to design platforms that provide rehabilitation therapy for disabled persons to help improve their motor functions Discusses the application of soft robotics for rehabilitation of upper and lower extremities separated by various limbs Offers readers the ability to find soft robotics devices, methods, and results for any limb, and then compare the results with other options provided in the book

Soft Actuators
Soft Actuators

Author: Kinji Asaka

Publisher: Springer

Published: 2014-11-17

Total Pages: 492

ISBN-13: 4431547673

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The subject of this book is the current comprehensive research and development of soft actuators, and encompasses interdisciplinary studies of materials science, mechanics, electronics, robotics and bioscience. As an example, the book includes current research on actuators based on biomaterials to provide future perspectives for artificial muscle technology. Readers can obtain detailed, useful information about materials, methods of synthesis, fabrication and measurements. The topics covered here not only promote further research and development of soft actuators but also lead the way to their utilization and industrialization. One outstanding feature of the book is that it contains many color figures, diagrams and photographs clearly describing the mechanism, apparatus and motion of soft actuators. The chapter on modeling is conducive to more extensive design work in materials and devices and is especially useful in the development of practical applications. Readers can acquire the newest technology and information about the basic science and practical applications of flexible, lightweight and noiseless soft actuators, which are quite unlike conventional mechanical engines and electric motors. The new ideas offered in this volume will provide inspiration and encouragement to researchers and developers as they explore new fields of applications for soft actuators.

Dielectric Elastomers as Electromechanical Transducers
Dielectric Elastomers as Electromechanical Transducers

Author: Federico Carpi

Publisher: Elsevier

Published: 2011-09-06

Total Pages: 344

ISBN-13: 0080557724

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Dielectric Elastomers as Electromechanical Transducers provides a comprehensive and updated insight into dielectric elastomers; one of the most promising classes of polymer-based smart materials and technologies. This technology can be used in a very broad range of applications, from robotics and automation to the biomedical field. The need for improved transducer performance has resulted in considerable efforts towards the development of devices relying on materials with intrinsic transduction properties. These materials, often termed as “smart or “intelligent , include improved piezoelectrics and magnetostrictive or shape-memory materials. Emerging electromechanical transduction technologies, based on so-called ElectroActive Polymers (EAP), have gained considerable attention. EAP offer the potential for performance exceeding other smart materials, while retaining the cost and versatility inherent to polymer materials. Within the EAP family, “dielectric elastomers , are of particular interest as they show good overall performance, simplicity of structure and robustness. Dielectric elastomer transducers are rapidly emerging as high-performance “pseudo-muscular actuators, useful for different kinds of tasks. Further, in addition to actuation, dielectric elastomers have also been shown to offer unique possibilities for improved generator and sensing devices. Dielectric elastomer transduction is enabling an enormous range of new applications that were precluded to any other EAP or smart-material technology until recently. This book provides a comprehensive and updated insight into dielectric elastomer transduction, covering all its fundamental aspects. The book deals with transduction principles, basic materials properties, design of efficient device architectures, material and device modelling, along with applications. Concise and comprehensive treatment for practitioners and academics Guides the reader through the latest developments in electroactive-polymer-based technology Designed for ease of use with sections on fundamentals, materials, devices, models and applications

Material Characterization of a Dielectric Elastomer for the Design of a Linear Actuator
Material Characterization of a Dielectric Elastomer for the Design of a Linear Actuator

Author: Alexander Tristan Helal

Publisher:

Published: 2017

Total Pages:

ISBN-13:

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Electrical motors and/or hydraulics and pneumatics cylinders are commonly used methods of actuation in mechanical systems. Over the last two decades, due to arising market needs, novel self-independent mobile systems such as mobility assistive devices have emerged with the help of new advancements in technology. The actuation criteria for these devices differ greatly from typical mechanical systems, which has made the implementation of classical actuators difficult within modern assistive devices. Among the numerous challenges, limited energy storage capabilities by mobile systems have restricted their achievable operational time. Furthermore, new expectations for device weight and volume, as well as actuator structural compliance, have added to this quandary. Electroactive polymers, a category of smart materials, have emerged as a strong contender for the use in low-cost efficient actuators. They have demonstrated great potential in soft robotic and assistive device/prosthetic applications due to their actuation potential and similar mechanical behaviour to human skeletal muscles. Dielectric Elastomers, in particular, have shown very promising properties for these types of applications. Their structures have shown large achievable deformation, while remaining light-weight, mechanically efficient, and low-cost. This thesis aims to characterize, and model the behaviour of 3MTM VHB polyacrylic dielectric elastomer, in order to establish a foundation for its implementation in a proposed novel linear actuator concept. In this thesis, a comprehensive experimental evaluation is accomplished, which resulted in the better understanding of the elastomer's biaxial mechanical and electro-mechanically coupled behaviours. Subsequently, a constitutive biaxial mechanical model was derived in order to provide a predictive design equation for future actuator development. This model proved effective in providing a predictive tool for the biaxial mechanical tensile response of the material. Finally, a simplified prototype was devised as a proof of concept. This first iteration applied experimental findings to validate the working principles behind the proposed actuator design. The results confirmed the proof of concept, through achieved reciprocal linear motion, and provided insight into the design considerations for prototype optimization and final actuator development.

Modeling of a Dielectric Elastomer
Modeling of a Dielectric Elastomer

Author: Mesfer Alkhathami

Publisher:

Published: 2019

Total Pages:

ISBN-13:

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Dielectric elastomer actuator (DEA) is a key element for the soft robots, which has received increasing attention. However, the main difficulties in modeling soft actuators such as dielectric elastomer actuators are time-dependent viscoelasticity and their material nonlinearity. It is important to consider the viscoelasticity of the dielectric elastomer (DE) to fully understand its mechanical behavior. However, so far only a few works have been presented considering the viscoelasticity of the DE material together with the effect of temperature and deformation. In this thesis, a dynamic electromechanical-coupled model for a rectangle dielectric elastomer a commonly used material (the acrylic elastomer VHB 4910) has been proposed, with taking into consideration of the influence of temperature, voltage, and frequency on the DE. The proposed model is based on the free energy physical-based principle, where the general Kelvin-Voigt model is applied to describe the viscoelasticity of the DE, and the Maxwell force together with the Electrostrictive force are considered. The influence of temperature and deformation on the DE is included in this model. The model in this study is a dynamic electromechanical model of a DE actuator, and can effectively describe the dynamic characteristics of the DE. By using the Differential Evolution, the model parameters were identified. The model was implemented and simulated in MATLAB, and the simulation and the actual experiment agrees to a great extent. The experimental test conducted in this study matches with the simulations results, which means that the proposed model can be practical to predict and describe DEAs electromechanical and viscoelastic behavior. Predicting the electromechanical and viscoelastic behavior of the DE is extremely useful for controlling a viscoelastic DEA and paving the way to improve the control performance, and also develops applications in soft robotics.

Bioinspired Liquid Crystal Elastomer (LCE) Based Soft Actuators with Multimodal Actuation
Bioinspired Liquid Crystal Elastomer (LCE) Based Soft Actuators with Multimodal Actuation

Author: Qiguang He

Publisher:

Published: 2021

Total Pages: 141

ISBN-13:

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Inspired by the biology, soft robots have drawn tremendous attention due to its large and continuous deformation, friendly human-machine interaction, large number of degrees of freedom (DOFs), capability of absorbing energy. They have been explored in broad applications ranging from dexterous soft gripper to the novel assistive devices. In the recent decade, numerous soft actuating materials and deformable structures have been developed to construct soft robots, including hydrogels, shape memory polymers (SMPs), dielectric elastomer actuators (DEAs), fluid elastomer actuators (FEAs) and magnetic actuators. However, those materials and structures have well-known limitations such as slow actuation speed, irreversibility, high voltage input and bulky controlling systems. Liquid crystal elastomers (LCEs), as newly emerging soft actuating materials, exhibit large and reversible deformation and versatile actuation modes. Based on the molecular structure, LCE can be viewed as a combination of liquid crystal molecules and polymer networks. When the LCE is heated above the critical temperature, it can generate large deformation because of the nematic-isotropic phase transition. However, in terms of the practical use of LCE, a few challenges exist such as lack of programmable operation and slow responsive speed for LCEs, which need to be addressed. In this dissertation, we first integrate flexible heating wire into LCE tube, forming electrically controlled soft tubular actuator. By selectively applying low electrical voltage, this soft tubular actuator can exhibit multiple actuation modes, such as different directional bending and homogeneous contraction. The LCE soft tubular actuator can also be integrated to construct untethered robot that can execute multiple functionalities. To address the slow responsive speed of LCE based soft actuator, we embed microfluidic channel into LCE, forming vascular LCE soft actuator. Through alternatively injecting hot and cold fluid into its internal fluidic channel, the vascular LCE soft actuator can generate fast actuation as well as recovery. In addition, by introducing the disulfide bonds into the LCE materials, the newly obtained vascular LCE based soft actuator has shown repairability and recyclability. Finally, we use electrospinning technique to fabricate LCE microfiber that can be actuated by NIR light. We demonstrate that the electrospun LCE fiber can be easily integrated to micro-robotic system and machine as artificial muscle fiber.