UNIVERSITI PUTRA MALAYSIA

DEVELOPING PROSTHETIC ARTIFICIAL MUSCLE ACTUATOR USING DIELECTRIC ELASTOMERS

HANEEN JAWAD MAHMOUD EL-HAMAD

FK 2016 157

© COPYRIG

HT UPM

DEVELOPING PROSTHETIC ARTIFICIAL MUSCLE ACTUATOR USING DIELECTRIC ELASTOMERS

By

HANEEN JAWAD MAHMOUD EL-HAMAD

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirements of the Degree of Master of Science

November 2016

© COPYRIG

HT UPM

COPYRIGHT

All material contained within the thesis, including without limitation text, logos, icons, photographs and all other artwork, is copyright material of Universiti Putra Malaysia unless otherwise stated. Use may be made of any material contained within the thesis for non-commercial purposes from the copyright holder. Commercial use of material may only be made with the express, prior, written permission of Universiti Putra Malaysia.

Copyright © Universiti Putra Malaysia

© COPYRIG

HT UPM

DEDICATION

I dedicate this dissertation to my beloved husband, who supported me in all possible ways and believed in me, to my wonderful parents, special sisters and family who were close despite the distance and to my beloved home, which awaits soaring.

© COPYRIG

HT UPM

i

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

DEVELOPING PROSTHETIC ARTIFICIAL MUSCLE ACTUATOR USING

DIELECTRIC ELASTOMERS

By

HANEEN JAWAD EL-HAMAD

November 2016

Chairman : Assoc. Prof. Siti Anom Ahmad, PhD

Faculty : Engineering

The loss of an upper limb can impair the ability to do even the simplest daily tasks. Robust prosthetic devices need to replicate the smooth movement, while maintaining the relatively high forces typical of the original limb. Dielectric elastomers (DEs) are potential candidates for actuating such prosthetic devices, however, DE materials are associated with material failure which limits their use as actuators. They also have been reported to generate low output force. This has limited DEs from being used for prosthetic devices that mainly require high output forces. This thesis proposes a conceptual design for a prosthetic arm, where the actuator is the DE material arranged in a suggested mechanism to generate high output force.

A two-bar mechanism was assumed to represent the human arm. The flexion action of the elbow was achieved by a slider-crank mechanism connecting the two bars actuated by DEs membranes. The DE actuator mechanism comprised of the arrangement of 1000 parallel planar linear DE membranes in parallel to maintain high output force and reduce the tensile stress. An Analytic model was developed to analyze the output force of the designed mechanism for a range of input electric fields. An electrical model was developed to model electrodes resistance and DE membrane leakage current resistance. Material and mechanism‟s dimensions and parameters were mathematically optimized

to produce the highest possible output force while maintaining the tensile stress and the input electric field below material failure points. An open loop system was designed to control the angular position of the arm. Mechanical and electrical power consumption calculations were carried out and the efficiency of the actuator and major energy dissipations were determined.

The actuator‟s generated force counteracts a compressive mechanical force of 97 N which is higher than reported actuator designs for arm prosthetics and is comparable to human muscle output force for arm flexion estimated between 40 N to 116 N. The 1000 DE membranes arrangement led to a reduction of the compressive stress over the material to be (30 kPa) which is well below the break point of 690kPa. The stimulant input electric field that is below the dielectric strength of the material which is 40MV/m. The critical input electric field at which electromechanical instability failure

© COPYRIG

HT UPM

ii

occurs has been increased by 2.05 times the critical input of voltage induced strain only. A high input electric field of range of 31.287 MV/m to 33.837 MV/m, yet with a power consumption of 248 mW per membrane is convenient for use in prosthetic devices. The electromechanical efficiency is 55.7% and the loss is mainly due to viscous energy dissipation and current leakage. The 1000 DE membrane arrangement led to the generation of high output force with lower input electric fields and lower stress over the material. Therefore, this actuator‟s design could be used as a prosthetic arm actuator replacing conventional actuators provided that further steps of realization are taken.

© COPYRIG

HT UPM

iii

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk Ijazah Sarjana Sains

MEMBANGUNKAN PROSTETIK ARTIFICIAL OTOT ACTUATOR

MENGGUNAKAN ELASTOMER DIELEKTRIK

Oleh

HANEEN JAWAD EL-HAMAD

November 2016

Pengerusi : Prof. Madya Siti Anom Ahamd, PhD

Fakulti : Kejuruteraan

Kehilangan salah satu anggota badan atas mampu memberi kesan kepada keupayaan melakukan sesuatu walaupun bagi tugasan harian yang mudah. Peranti prostetik yang tegap perlu meniru pergerakan lancar, di samping mengekalkan kuasa-kuasa tinggi anggota badan asal. Elastomer Dielektrik (DEs) adalah calon-calon berpetensi untuk menjadi penggerak kepada peranti prostetik tersebut. Walau bagaimanapun, bahan-bahan DE dikaitkan dengan kegagalan bahan yang menghadkan penggunaannya sebagai penggerak. Mereka juga telah dilaporkan untuk menjana daya keluaran yang rendah. Ini telah menghadkan DEs daripada digunakan untuk peranti prostetik yang sebahagian besarnya memerlukan kuasa output yang tinggi. Tesis ini mencadangkan reka bentuk konsep untuk lengan prostetik, yang mana penggeraknya adalah bahan DE yang diatur dalam mekanisme yang dicadangkan untuk menjana kuasa output yang tinggi.

Mekanisme dua-bar telah diandaikan untuk mewakili lengan manusia. Tindakan fleksi siku telah dicapai oleh mekanisme gelangsor-engkol menghubungkan dua bar yang digerakkan oleh membran-membran DEs. Mekanisme penggerak DE terdiri daripada susunan 1000 satah linear selari membrane-membran DE secara serentak untuk mengekalkan daya hasil yang tinggi dan mengurangkan tekanan tegangan. Satu model analitik telah dibangunkan untuk menganalisis daya keluaran mekanisme yang direka untuk pelbagai input medan elektrik. Satu model elektrik telah dibangunkan untuk model rintangan elektrod dan kebocoran rintangan membran DE semasa. Material dan dimensi-dimensi mekanisme dan parameter-parameter telah dioptimumkan secara matematik untuk menghasilkan daya output tertinggi sambil mengekalkan tekanan tegangan dan medan elektrik input di bawah titik kegagalan material. Satu sistem gelung terbuka telah direka untuk mengawal kedudukan sudut lengan. Pengiraan penggunaan kuasa mekanikal dan elektrik telah dijalankan dan kecekapan penggerak dan penghapusan tenaga utama telah ditentukan.

Kuasa dijana penggerak yang bertindak menentang kuasa mekanikal mampatan 97 N iaitu lebih tinggi daripada reka bentuk penggerak yang dilaporkan untuk prostetik lengan dan boleh dibandingkan dengan kuasa output otot manusia untuk fleksi lengan yang dianggarkan antara 40 N 116 N. 1000 susunan membran-membran DE membawa

© COPYRIG

HT UPM

iv

kepada pengurangan tekanan mampatan untuk menjadi (30 kPa) yang jauh lebih rendah daripada titik rehat 690kPa. Input perangsang medan elektrik yang di bawah kekuatan dielektrik material 40MV / m. Input medan elektrik yang kritikal yang mana kejadian kegagalan ketidakstabilan elektromekanik telah meningkat sebanyak 2.05 kali input kritikal ketegangan yang disebabkan oleh voltan sahaja. Medan elektrik input tinggi pelbagai 31,287 MV / m untuk 33,837 MV / m, namun dengan penggunaan kuasa 248 mW setiap membran adalah mudah untuk digunakan dalam peranti prostetik. Kecekapan elektromekanik adalah 55.7% dan kerugian adalah disebabkan oleh penghapusan tenaga likat dan kebocoran semasa. Susunan 1000 membran DE membawa kepada penjanaan daya keluaran tinggi dengan input elektrik yang lebih rendah dan tekanan lebih rendah terhadap material. Oleh itu, reka bentuk penggerak ini boleh digunakan sebagai penggerak lengan prostetik menggantikan penggerak konvensional dengan syarat langkah-langkah lanjut diambil.

© COPYRIG

HT UPM

v

ACKNOWLEDGEMENTS

All praise and thanks to Allah, and peace and blessings be upon Muhammad, his Messenger.

I would like to thank my thesis supervisor Prof. Madya Dr. Siti Anom Ahmad, who was consistently driving me to learn and improve in many ways. She made my experience easier and much more valuable and was always ready when I was. I would like to thank my co-supervisor Dr. Asnor Juraiza Bt. Ishak for supporting my thoughts and ideas.

I would also like to acknowledge Dr. Rami Al-Dirini as the second reader of this thesis, and I am gratefully indebted to his very valuable comments.

I finally express my gratitude to my dear friend and sister, Fatima and dear friend and colleague, Nursaida.

© COPYRIG

HT UPM

© COPYRIG

HT UPM

vii

This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of the Supervisory Committee were as follows:

Siti Anom Bt. Ahmad, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman)

Asnor Juraiza Bt. Ishak, PhD Senior Lecturer Faculty of Engineering Universiti Putra Malaysia (Member)

____________________________ ROBIAH BINTI YUNUS, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia Date:

© COPYRIG

HT UPM

viii

Declaration by graduate student I hereby confirm that: This thesis is my original work; Quotations, illustrations and citations have been duly referenced; This thesis has not been submitted previously or concurrently for any other degree

at any other institutions; Intellectual property from the thesis and copyright of thesis are fully-owned by

Universiti Putra Malaysia, as according to the Universiti Putra Malaysia (Research) Rules 2012;

Written permission must be obtained from supervisor and the office of Deputy Vice-Chancellor (Research and Innovation) before thesis is published (in the form of written, printed or in electronic form) including books, journals, modules, proceedings, popular writings, seminar papers, manuscripts, posters, reports, lecture notes, learning modules or any other materials as stated in the Universiti Putra Malaysia (Research) Rules 2012;

There is no plagiarism or data falsification/fabrication in the thesis, and scholarly integrity is upheld as according to the Universiti Putra Malaysia (Graduate Studies) Rules 2003 (Revision 2012-2013) and the Universiti Putra Malaysia (Research) Rules 2012. The thesis has undergone plagiarism detection software.

Signature: _______________________ Date: __________________ Name and Matric No.: _________________________________________

© COPYRIG

HT UPM

ix

Declaration by Members of Supervisory Committee This is to confirm that: The research conducted and the writing of this thesis was under our supervision; Supervision responsibilities as stated in the Universiti Putra Malaysia (Graduate

Studies) Rules 2003 (Revision 2012-2013) are adhered to. Signature: _________________________ Name of Chairman of Supervisory Committee: _________________________ Signature: _________________________ Name of Member of Supervisory Committee: _________________________

Siti Anom Bt. Ahmad, PhD

Asnor Juraiza Bt. Ishak, PhD

© COPYRIG

HT UPM

x

TABLE OF CONTENTS

Page ABSTRACT i ABSTRAK iii ACKNOWLEDGEMENTS v APPROVAL vi DECLARATION viii LIST OF TABLES xii LIST OF FIGURES xiii LIST OF ABBREVIATIONS xv CHAPTER 1 INTRODUCTION 1

1.1 Problem Statement 2 1.2 Objectives 2 1.3 Scope of Work 2 1.4 Thesis Chapters Outline 3

2 BACKGROUND AND LITERATURE REVIEW 4

2.1 Existing Prostheses Actuator Technologies 4 2.2 Artificial Muscles Actuators 6 2.3 Dielectric Elastomer Materials 10 2.4 Dielectric Elastomer Material Models 11 2.5 Dielectric Elastomer Actuator Designs 13 2.6 Actuation and Control Schemes for Dielectric Elastomer Actuators 14 2.7 Summary 14

3 METHODOLOGY 15

3.1 Analytic Model Development 15 3.1.1 DE Material: Viscoelastic Model 15 3.1.2 Conceptual Mechanical Design 18 3.1.3 Proposed DE Membranes Arrangement 20 3.1.4 Actuator Mathematical Model 21

3.2 Actuator Design 24 3.2.1 Electrical Material Model 24 3.2.2 Actuator State Diagram 25 3.2.3 Actuator Power Source and Efficiency 26

3.3 Actuator Parameters Selection 27 3.3.1 Mechanical Parameters 27 3.3.2 Input Electric Field Selection 27

4 RESULTS AND DISCUSSION 28

4.1 Actuator Design Parameters 28 4.1.1 Mechanical and Material Parameters 28 4.1.2 Design Input Parameters 32

4.2 Mathematical Model Simulation of the DE Actuator 33 4.2.1 Response of the Actuator 33

© COPYRIG

HT UPM

xi

4.2.2 Response of the Actuator with Different Values of DE Membranes 35 4.2.3 Response of the Actuator at Critical Input Electric Field 36

4.3 Open Loop Control Simulation 36 4.4 Power Consumption 37 4.5 Discussion 38

5 CONCLUSIONS AND FUTURE WORK 40

5.1 Conclusion 40 5.2 Future Work 41

REFERENCES 42 APPENDICES 48BIODATA OF STUDENT 56 LIST OF PUBLICATIONS 57

© COPYRIG

HT UPM

xii

LIST OF TABLES

Table Page

2-1 Comparison of candidate actuator technologies including electroactive polymers and non-polymer actuators with natural muscle in terms of different properties [7] 7

2-2 Summarization of active polymers types [23] 8

‎2-3 A comparison of dielectric and mechanical properties of different material types of elastomers [3] 11

4-1 Summary of selected and calculated mechanical and material parameters 31

‎4-2 Comparison between data points from both responses, Zhao et al. model and the actuator response where the behavior is similar yet the values are different. 35

© COPYRIG

HT UPM

xiii

LIST OF FIGURES

Figure Page

3-1 Schematic of a planar DE membrane with defined lengths, forces and applied voltage (a) unloaded DE membrane, and (b) loaded DE membrane [50] 16

3-2 Two network rheological viscoelastic model. The spring network represents the DE elastic response and the spring-dashpot represents the viscoelastic response 17

3-3 Conceptual mechanical structure of the actuator representing the upper arm and forearm linked at a joint representing the elbow joint. Dimensions and symbols are defined. 18

3-4 Free body diagram of member 'L2' showing applied forces 19

‎3-5 Free body diagram at point A of the mechanical structure showing forces applied 19

‎3-6 Force diagram for member „L1‟. The equations of the force value are shown at points A, B and C. The maximum force value is at point C 20

3-7 Two dimension DE membrane set upright with the forces acting on it are the compressive force and the weight of the DE material which act downward and the applied voltage induced Maxwell force which is acting upwards 21

3-8 Schematic of the electrical model of the DE material which is represented by a capacitor in parallel with current leakage resistance and a series electrode resistance. (a) DE electrical circuit model for one DE membrane (b) Parallel DE membranes circuit model for „n‟ DE membranes 24

3-9 Diagram of states of the DE actuator in an open loop control schematic. The starting state is the angular position 25

4-1 The mechanical force output with values of distance „b‟, for the set of lengths of „L3‟. The force is decreasing with increasing distance „b‟ 29

4-2 The mechanical force output with values of length „L3‟, for the set of lengths of „b‟. The force is almost constant with increasing length „L3‟ 29

4-3 Elongation percentage of DE membrane with length „L3‟, for the set of distances of „b‟. For higher values of distance „b‟ the elongation percentage decreases with increasing length „L3‟ 30

© COPYRIG

HT UPM

xiv

4-4 Elongation percentage of DE membrane with distance „b‟, for the set of lengths of „b‟. The elongation percentage increases with increasing distance „b‟ 30

4-5 Decreasing mechanical force with increasing angular position 32

4-6 Approximated angular position as a function of the input electric field. Single segment linear approximation curve is shown with clear high mean error 33

4-7 Approximated angular position as a function of the input electric field. Five segment nonlinear approximation curve is shown with acceptable mean error 33

4-8 DE actuator stretch function responses shown for selected input angular positions. The response represents the steady state for each stretch value which corresponds to a specified angular position 34

‎4-9 DE material model response to input electric field. The stretch is only induced by electric field as shown in [50] 34

‎4-10 DE actuator stretch function response for the same angular position at different numbers of parallel DE membranes ranging from 1 to 1000 35

4-11 DE actuator stretch response for the same angular position at different values of input electric field. The input electric field is normalized as a unit of the critical value defined by [50]. Values above 2.05 result in instability of the material 36

4-12 Response of single input to the DE actuator model using Simulink. A single input angular position resulted in a correct behavior. Yet the value of the stretch is higher than expected 37

4-13 Response of consecutive input to the DE actuator model using Simulink. Consecutive input angular positions resulted in a correct behavior. Yet the value of the stretch is higher than expected and increasing at a higher rate than expected 37

© COPYRIG

HT UPM

xv

LIST OF ABBREVIATIONS

DE Dielectric Elastomer

EAP Eloctroactive Polymers

DC Direct current

SMA Shape Memory Alloy

PAM Pneumatic Artificial Muscle

IPMC Ionic Polymer Metal Composite

CNT Carbon Nanotube

EAPap Electrostrictive EAP Paper

ER Rheological Fluids

LCE Liquid Crystals

PU PolyUrethanes

DoF Degree of Freedom

© COPYRIG

HT UPM

© COPYRIG

HT UPM

1

Chapter 1

Introduction

The loss of an upper limb for an individual is quite limiting and highly affects the ability to do even the simplest tasks on a daily basis. Estimations of numbers of major upper limb amputees currently in the US are about 227,000 [1]. 72% of such amputations is estimated to occur in active and productive individuals aging below 65 years [1]. The high impact of upper limb amputations that is reflected physically as well as emotionally on the life of the amputee has led to continuous attempts to restore the function of the lost limb. Various technologies and mechanisms of prosthetic devices were developed, yet prosthetic devices rejection rates among amputees is generally high [2]. This is due to different factors including lack of rehabilitation and cost, as well as problems related to current technologies of prosthetic arms of body-powered and myoelectric prosthetic devices where rejection rates reached 50% and 39% respectively [2]. Such available prostheses devices are not competent with the original functionality of the lost limb in terms of control, feedback , smooth movements, speed of operation and weight to name a few [3]–[5]. Therefore the need for new technologies in the actuation of prosthetic devices is apparent.

In the recent years, many researchers worked on the development of new actuation technologies in place of traditional technologies for prosthetic devices [6]. Artificial muscles as a new actuator technology were suggested for upper limb prosthetic devices [7]. Artificial muscles are defined as materials that can contract, expand or rotate in response to a variety of stimuli [7], [8]. They behave like natural muscles by contracting and expanding, thus the name artificial muscle. Different types of stimuli for artificial muscles include electric fields, chemical solutions, temperature, light photons and magnetic fields [9]. An electrically stimulated artificial muscle is favorable in the design of prosthetic actuators due to the easy access to the stimuli source and the normal environment conditions required [7].

Specific types of electrically stimulated artificial muscles are Dielectric Elastomers (DE). They are dielectric materials sandwiched between stretchable electrodes and are activated by the application of electric field [10], [11]. They are mainly made of silicones or acrylics and are readily available as adhesives [12]. DE materials have been investigated experimentally and models were developed ranging from a linear Hooke model, nonlinear hyperelastic models [13] and including viscoelasticity [14]. DEs can expand to high strains above 100% [10], are lightweight and capable of generating high output forces [11]. They are also well comparable to human muscle in terms of energy density, fast response and output stress [7], [10]. However, DEs require very high actuation voltages in the range of kilo volts to achieve the high elongation strains and stresses. Yet they are still approachable as prosthetic devices actuators since the input power consumption is measured in watts [7]. However, such high actuation voltages limit the use of the material itself since the actuation voltage is close to the dielectric breakdown thresholds [15]. Therefore DEs have been suggested as actuators for prosthetic arms [7], and actuator designs were reported for upper limb prosthetics of fingers, hands or elbow motion. Specifically, designs reported to achieve the elbow flexion range of motion and replace a bicep muscle in doing so have either

© COPYRIG

HT UPM

2

been very large to be installed on humans [16] or generated low output forces [7], [17] that are insufficient for actual implementation as a prosthetic arm.

This thesis will present a design for a mechanism employing DE materials to actuate a conceptual prosthetic arm. The range of motion will be that of the elbow flexion. The approach will be to select and modify a DE material model to overcome limitations accompanying the use of these materials and propose a mechanism to generate sufficient force through designing a mechanical structure and a DE membranes arrangement. The outcome of this thesis will be a verification of a prosthetic arm that produces force that is comparable to human muscle force achieving a similar range of motion using DE materials. It will also propose a functional actuator to replace conventional motor and gear systems in prosthetic arms and provide simpler and less complex systems as well as employ the potential of DE materials in a new field of possible applications.

1.1 Problem Statement

DE materials are associated with material failure modes such as electromechanical instability, dielectric strength failure, viscoelasticity and current leakage which have limited their use as actuators. The question is how to select a material model that best addresses such failure modes and modify it to meet the requirements of the suggested design?

The output force of the natural arm muscle performing flexion of the elbow is estimated to be in the range of 40 N to 116 N [18]. Reported DE material actuators generated lower forces relative to the size. The question is how to design a mechanism that generates a comparable output force to human bicep muscle?

1.2 Objectives

The objectives of this thesis is to find solutions to the problems mentioned in section (1.1), this includes:

1. To select and modify a DE material model that addresses limitations accompanying the use of these materials.

2. To identify an output force comparable to human muscle for the flexion action of the elbow through proposing a DE membranes arrangement.

1.3 Scope of Work

This thesis will present a new design for a prosthetic arm system where it will include studying and developing a selected model of the selected material, designing the actuator mechanism and performing mathematical optimization for selection of parameters of both the mechanical structure and the material variables. The actuator model verification will be presented through mathematical simulation.

However, this thesis will not include the investigation and design of mechanisms other than the one degree of freedom flexion of the elbow range of motion. The conceptual design proposed will not include modeling of a cosmetic prosthetic arm and will not go beyond roughly estimated bar measures of the forearm and upper arm of an average

© COPYRIG

HT UPM

3

human. Also a study or analysis of possible control signal sources in prosthetic devices such as EMG signals is beyond the scope of this thesis. Control methods and power sources are briefly introduced but the thesis will not include a study or analysis of these methods.

1.4 Thesis Chapters Outline

Chapter 2 is the literature review which will present an insight to designed prosthetic arms using conventional actuators and will highlight the benefits of using artificial muscles in prosthetic devices. The definition of artificial muscles and the classification of different types according to different stimuli are listed. The presentation of detailed properties of DE materials follows with a description of the operating concept of such materials. An overview of mathematical models of DEs varying in approaches and considerations to associated limitations of DE materials is listed. A list of DE material actuators designed for prosthetic devices is discussed and the outputs of each design are compared.

In Chapter 3, the methodology is explained. The analytical model development of the DE material is stated along with the mechanical design of the conceptual arm. The actuator design including the electrical model of the material is explained. The optimization process of the material and mechanical parameters selection is stated leading to geometry and dimensions selection. The actuator state block diagram and the open loop control are designed.

In chapter 4, the results of the model verification and the open loop control are stated and discussed. Chapter 5 follows with conclusions and remarks for future work.

© COPYRIG

HT UPM

42

REFERENCES

[1] K. Ziegler-Graham, E. J. MacKenzie, P. L. Ephraim, T. G. Travison, and R. Brookmeyer, “Estimating the prevalence of limb loss in the United States:

2005 to 2050,” Arch Phys Med Rehabil, vol. 89, no. 3, pp. 422–429, 2008.

[2] L. Resnik et al., “Advanced upper limb prosthetic devices: Implications for

upper limb prosthetic rehabilitation,” Arch. Phys. Med. Rehabil., vol. 93, no. 4, pp. 710–717, 2012.

[3] J. D. Nam, H. R. Choi, J. C. Koo, Y. K. Lee, and K. J. Kim, “Dielectric elastomers for artificial muscles,” Electroact. Polym. Robot. Appl., pp. 37–48, 2007.

[4] K. Meijer, M. Rosenthal, and R. J. Full, “Muscle-like actuators? A comparison between three electroactive polymers,” Proc. SPIE - Int. Soc. Opt. Eng., vol. 4329, pp. 7–15, 2001.

[5] R. Pelrine et al., “Dielectric elastomer artificial muscle actuators: toward

biomimetic motion,” Proc. SPIE, vol. 4695, no. 3, pp. 126–137, 2002.

[6] A. J. Veale and S. Xie, “Towards compliant and wearable robotic orthoses: A

review of current and emerging actuator technologies,” Medical Engineering

and Physics, vol. 38, no. 4. pp. 317–325, 2016.

[7] H. Herr and R. Kornbluh, “New horizons for orthotic and prosthetic

technology: artificial muscle for ambulation,” Smart Struct. Mater. Electroact.

Polym. Actuators Devices, vol. 5385, pp. 1–9, 2004.

[8] Y. Bar-Cohen, “EAP as Artificial Muscles - Progress and Challenges,” Smart

Struct. Mater., pp. 1–6, 2004.

[9] R. Samatham et al., “Active polymers: An overview,” Electroact. Polym.

Robot. Appl. Artif. Muscles Sensors, pp. 1–36, 2007.

[10] E. Biddiss and T. Chau, “Dielectric elastomers as actuators for upper limb

prosthetics: Challenges and opportunities,” Med. Eng. Phys., vol. 30, no. 4, pp. 403–418, 2008.

[11] J.-S. Plante and S. Dubowsky, “On the Nature of Dielectric Elastomer

Actuators and Its Implications for Their Design,” Proc. SPIE, p. 61681J 1-11, 2006.

[12] X. Zhang, C. Lowe, M. Wissler, B. Jahne, and G. Kovacs, “Dielectric

elastomers in actuator technology,” Adv. Eng. Mater., vol. 7, no. 5, pp. 361–

367, 2005.

[13] G. Kofod, “Dielectric elastomer actuators,” 2001.

[14] E. Yang, M. Frecker, and E. M. Mockensturm, “Viscoelastic model of

© COPYRIG

HT UPM

43

dielectric elastomer membranes,” Smart Struct. Mater., vol. 5759, pp. 82–93, 2005.

[15] J. Madden et al., “Artificial muscle technology:Physical principles and Naval

prospects,” IEEE J. Ocean. Eng, vol. 29, no. 3, p. 29,3, 7006-28, 2004.

[16] G. Kovacs, “Arm wrestling robot driven by dielectric elastomer actuators,”

Proc. First IEEE/RAS-EMBS Int. Conf. Biomed. Robot. Biomechatronics,

2006, BioRob 2006, vol. 2006, pp. 260–265, 2006.

[17] O. Al-Habahbeh, H. Al-Hamad, L. Al-Sakka, and H. Al-Sahori, “Viable

Design of an Arm Prosthesis System,” Int. J. Adv. Sci. Technol., vol. 65, pp. 1–

18, 2014.

[18] National Aeronautics and Space Administration, “Human Performance

Capabilities,” 1995.

[19] R. Weir and J. W. Sensinger, “Design of artificial arms and hands for

prosthetic applications,” Biomed. Eng. Des. Handb., pp. 537–598, 2009.

[20] V. O. Del Cura, F. L. Cunha, M. L. Aguiar, and A. Cliquet, “Study of the

Different Types of Actuators and Mechanisms fpr Upper Limb Prostheses,”

Artif. Organs, vol. 27, no. 6, pp. 507–516, 2003.

[21] H. Herr, G. P. Whiteley, and D. Childress, “Cyborg Technology - Biomimetic Orthotic and Prosthetic Technology,” Biol. Inspired Intell. Robot., pp. 103–

144, 2003.

[22] D. Childress, “Historical Aspects of Powered Limb Prostheses,” Clin.

prosthetics Orthot., vol. 9, no. 1, pp. 2–13, 1985.

[23] Y. Bar-Cohen, “Electroactive Polymers as Artificial Muscles – Reality and Challenges,” in Structures, Structural Dynamics, and Materials Conference

(SDM), 2001.

[24] Y. Bar-Cohen, T. Xue, and S. S. Lih, “Polymer Piezoelectric Transducers for

Ultrasonic NDE,” NDTnet, vol. 1, no. 9, pp. 1–8, 1996.

[25] R. H. Baughman, “Playing with Nature‟s Artificial Game Muscles,” Am.

Assoc. Adv. Sci., vol. 308, no. 5718, pp. 63–65, 2005.

[26] R. Kornbluh, R. Pelrine, H. Prahlad, and R. Heydt, “Electroactive polymers: an

emerging technology for MEMS,” vol. 5344, pp. 13–27, 2004.

[27] M. Zrinyi, “Intelligent polymer gels controlled by magnetic fields,” Colloid

Polym. Sci., vol. 278, no. 2, pp. 98–103, 2000.

[28] H. Ichijo et al., “Thermo-responsive gels,” Radiat. Phys. Chem., vol. 46, no. 2, pp. 185–190, Aug. 1995.

© COPYRIG

HT UPM

44

[29] Y. Bar-Cohen, “Artificial Muscles using Electroactive Polymers (EAP):

Capabilities, Challenges and Potential,” pp. 1–14, 2005.

[30] T. Tanaka, N. Izumi, S.-T. Sun, and S. Ueno-Nishio, “Collapse of Gels in an

Electric Field,” Science (80-. )., vol. 218, no. 4571, pp. 467–469, 1982.

[31] K. J. Kim and M. Shahinpoor, “A novel method of manufacturing three-dimensional ionic polymer-metal composites (IPMCs) biomimetic sensors, actuators and artificial muscles,” Polymer (Guildf)., vol. 43, no. 3, pp. 797–

802, 2001.

[32] R. H. Baughman, “Conducting polymer artificial muscles,” Synth. Met., vol. 78, no. 3, pp. 339–353, 1996.

[33] J. Su, J. S. Harrison, and T. St Clair, “Novel polymeric elastomers for

actuation,” Appl. Ferroelectr. 2000. ISAF 2000. Proc. 2000 12th IEEE Int.

Symp., vol. 2, pp. 811–814, 2000.

[34] C. Hackl, H. Tang, R. D. Lorenz, L. Turng, and D. Schröder, “A Multi-Physics Model of Planar Electro-Active Polymer Actuators,” vol. 0, no. C, pp. 2125–

2130, 2004.

[35] R. Pelrine, R. Kornbluh, Q. Pei, and J. Joseph, “High-speed electrically actuated elastomers with strain greater than 100%,” Science, vol. 287, no. 5454, pp. 836–9, 2000.

[36] R. Shankar, T. K. Ghosh, and R. J. Spontak, “Dielectric elastomers as next-generation polymeric actuators,” Soft Matter, vol. 3, no. 9, p. 1116, 2007.

[37] R. Pelrine and R. Kornbluh, “Introduction : History Of Dielectric Elastomer

Actuators,” Dielectr. Elastomers as Electromechanical Transducers, pp. 1990–

1992, 2008.

[38] Q. Zhang et al., “An all-organic composite actuator material with a high dielectric constant.,” Nature, vol. 419, no. 6904, pp. 284–287, 2002.

[39] R. Pelrine, R. Kornbluh, and G. Kofod, “High-strain actuator materials based on dielectric elastomers,” Adv. Mater., vol. 12, no. 16, pp. 1223–1225, 2000.

[40] K. Jung et al., “Development of enhanced synthetic elastomer for energy-efficient polymer actuators,” Smart Mater. Struct., vol. 16, pp. S288–S294, 2007.

[41] N. H. Chuc, J. C. Koo, Y. K. Lee, J. D. Nam, and H. R. Choi, “Artificial

Muscle Actuator Based on the Synthetic Elastomer,” Int. J. Control. Autom.

Syst., vol. 6, no. 6, pp. 894–903, 2009.

[42] J.-S. Plante and S. Dubowsky, “On the properties of dielectric elastomer

actuators and their design implications,” Smart Mater. Struct., vol. 16, no. 2, pp. S227–S236, 2007.

© COPYRIG

HT UPM

45

[43] P. Sommer-larsen, J. Hooker, G. Kofod, K. West, M. Benslimane, and P. Gravesen, “Response of dielectric elastomer actuators,” Struct. Mater., vol. 4329, pp. 157–163, 2001.

[44] J.-S. Plante and S. Dubowsky, “On the performance mechanisms of Dielectric Elastomer Actuators,” Sensors Actuators, A Phys., vol. 137, no. 1, pp. 96–109, 2007.

[45] N. Goulbourne, “Electroelastic Modeling of Dielectric Elastomer Membrane

Actuators,” no. August, p. 165, 2005.

[46] M. Wissler and E. Mazza, “Modeling of a pre-strained circular actuator made of dielectric elastomers,” Sensors Actuators, A Phys., vol. 120, no. 1, pp. 184–

192, 2005.

[47] M. Wissler and E. Mazza, “Modeling and simulation of dielectric elastomer

actuators,” Smart Mater. Struct., vol. 14, pp. 1396–1402, 2005.

[48] R. Pelrine, R. Kornbluh, J. Joseph, R. Heydt, Q. Pei, and S. Chiba, “High-field deformation of elastomeric dielectrics for actuators,” Mater. Sci. Eng. C, vol. 11, no. 2, pp. 89–100, 2000.

[49] Z. Suo, “Theory of dielectric elastomers,” Acta Mech. Solida Sin., vol. 23, no. 6, pp. 549–578, 2010.

[50] X. Zhao, J. A. K. Soo, and Z. Suo, “Nonequilibrium Thermodynamics Of

Dielectric Elastomers,” Int. J. Appl. Mech., vol. 3, no. 2, pp. 203–217, Jun. 2011.

[51] L. Liu, Y. Liu, and J. Leng, “Theory progress and applications of dielectric

elastomers,” Int. J. Smart Nano Mater., vol. 4, no. 3, pp. 199–209, 2013.

[52] C. C. Foo, S. Cai, J. A. K. Soo, S. Bauer, and Z. Suo, “Model of dissipative

dielectric elastomers,” J. Appl. Phys., vol. 111, no. 3, 2012.

[53] Y. Wang, H. Chen, Y. Wang, and D. Li, “A General Visco-Hyperelastic Model for Dielectric Elastomers and Its Efficient Simulation Based on Complex Frequency Representation,” Int. J. Appl. Mech., vol. 7, no. 1, p. 1550011, 2015.

[54] M. Moscardo, X. Zhao, Z. Suo, and Y. Lapusta, “On designing dielectric

elastomer actuators,” J. Appl. Phys., vol. 104, no. 9, pp. 1–7, 2008.

[55] J. Zhou, W. Hong, X. Zhao, Z. Zhang, and Z. Suo, “Propagation of instability

in dielectric elastomers,” Int. J. Solids Struct., vol. 45, no. 13, pp. 3739–3750, 2008.

[56] X. Zhao, W. Hong, and Z. Suo, “Electromechanical hysteresis and coexistent

states in dielectric elastomers,” Phys. Rev. B - Condens. Matter Mater. Phys., vol. 76, no. 13, pp. 1–9, 2007.

© COPYRIG

HT UPM

46

[57] J.-S. Plante and S. Dubowsky, “Large-scale failure modes of dielectric elastomer actuators,” Int. J. Solids Struct., vol. 43, no. 25–26, pp. 7727–7751, 2006.

[58] J.-S. Plante, L. M. Devita, and S. Dubowsky, “A road to practical dielectric

elastomer actuators based robotics and mechatronics: discrete actuation,” Proc.

SPIE 6524, Smart Struct. Mater. 2007 Electroact. Polym. Actuators Devices, vol. 6524, pp. 652406-652406–15, 2007.

[59] P. Brochu and Q. Pei, “Advances in dielectric elastomers for actuators and

artificial muscles,” Macromol. Rapid Commun., vol. 31, no. 1, pp. 10–36, 2010.

[60] Y. Bar-Cohen, “Biologically inspired intelligent robots using artificial

muscles,” Strain, vol. 41, no. 1, pp. 19–24, 2005.

[61] F. Carpi and É. Smela, Biomedical applications of electroactive polymer

actuators. 2009.

[62] A. Wingert, M. D. Lichter, and S. Dubowsky, “On the design of large degree-of-freedom digital mechatronic devices based on bistable dielectric elastomer actuators,” IEEE/ASME Trans. Mechatronics, vol. 11, no. 4, pp. 448–456, 2006.

[63] C. Bolzmacher, J. Biggs, and M. Srinivasan, “Flexible dielectric elastomer

actuators for wearable human-machine interfaces - art. no. 616804,” Smart

Struct. Mater. 2006 Electroact. Polym. Actuators Devices, vol. 6168, p. 16804, 2006.

[64] Q. Pei, R. Pelrine, M. Rosenthal, S. Stanford, H. Prahlad, and R. Kornbluh, “Recent progress on electroelastomer artifical muscles and their application

biomimetic robots,” Electroact. Polym. Actuators Devices, vol. 5385, pp. 41–

50, 2004.

[65] F. Carpi and D. De Rossi, “Contractile dielectric elastomer actuator with

folded shape,” Smart Struct. Mater., vol. 6168, p. 61680D–61680D–6, 2006.

[66] F. Carpi, A. Migliore, G. Serra, and D. De Rossi, “Helical dielectric elastomer

actuators,” Smart Mater. Struct., vol. 14, no. 6, p. 1210, 2005.

[67] M. Y. Jung et al., “Fabrication and characterization of linear motion dielectric

elastomer actuators,” Smart Struct. Mater. 2006 Electroact. Polym. Actuators

Devices, vol. 6168, p. 616824, 2006.

[68] L. Eitzen, T. Hoffstadt, and J. Maas, “Power electronics concepts for driving

EAP actuators,” 2013, vol. 8687, p. 86870D.

[69] J. Maas, C. Grafa, and L. Eitzena, “Control Concepts for Dielectric Elastomer

Actuators,” vol. 7976, pp. 1–12, 2011.

© COPYRIG

HT UPM

47

[70] K. Jung, K. J. Kim, and H. Ryeol, “A self-sensing dielectric elastomer actuator,” vol. 143, pp. 343–351, 2008.

[71] T. A. Gisby et al., “Closed loop control of dielectric elastomer actuators,” vol.

7976, pp. 1–9, 2011.

[72] F. Dai, X. Qi, S. Zheng, S. Xiong, and J. Hu, “Integrated Driving and Measurement System for Dielectric Elastomer Actuators,” in International

Conference on Robotics and Biomimetics, 2007, pp. 1833–1837.

[73] P. Thummala, Z. Zhang, M. A. E. Andersen, and S. Rahimullah, “Parallel input

parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators,” in Electroactive Polymer Actuators and

Devices (EAPAD), 2014, vol. 9056, 9056.

[74] T. A. Gisby, E. P. Calius, S. Xie, and I. A. Anderson, “An adaptive control

method for dielectric elastomer devices,” vol. 6927, pp. 1–8, 2008.

[75] M. Randazzo, M. Fumagalli, F. Nori, G. Metta, and G. Sandini, “Force control

of a tendon driven joint actuated by dielectric elastomers,” pp. 2–5.

[76] S. Reitelshöfer et al., “Dielectric elastomer actuators - On the way to new actuation-systems driving future assistive, compliant and safe robots and prostheses,” Proc. IEEE RAS EMBS Int. Conf. Biomed. Robot.

Biomechatronics, pp. 803–808, 2014.

[77] C. C. Gordon et al., “Anthropometric Survey of U.S. Army Personnel: Pilot Summary Statistics,” Security, 1989.

[78] J. E. Uellendahl, “Prosthetic primer: Materials used in prosthetic part II,”

inMotion Mag., vol. 8, no. 6, p. 9, 1998.

[79] 3M, “3M VHB TM Adhesive Transfer Tapes with Adhesive 100MP,” Tech.

data, pp. 1–5.

[80] R. Weir, Design of Artificial Arms and Hands for Prosthetic Applications. 2004.

© COPYRIG

HT UPM

57

LIST OF PUBLICATIONS

Conference Paper

EL-Hamad, H., Ahmad, S.a., Ishak, A.J., “Modelling of High Output Force Dielectric

Elastomer Actuator,” 5th International Conference on Engineering and Innovative Materials (ICEIM 2016)

Published Journal

EL-Hamad, H., Ahmad, S.a., Ishak, A.J., “Modelling of High Output Force Dielectric

Elastomer Actuator,” International Journal of Mechanical Engineering and Robotics Research Vol. 6, No. 2, March 2017