Development of Strategies to Reduce Energy Expenditure for Lower-Limb Active Or- Thoses Author: Daniel Sanz Merodio Advisor: Dr

Total Page:16

File Type:pdf, Size:1020Kb

Development of Strategies to Reduce Energy Expenditure for Lower-Limb Active Or- Thoses Author: Daniel Sanz Merodio Advisor: Dr ESCUELA TECNICA SUPERIOR DE INGENIEROS INDUSTRIALES DEVELOPMENT OF STRATEGIES TO REDUCE ENERGY EXPENDITURE FOR LOWER-LIMB ACTIVE ORTHOSES DOCTORAL THESIS Daniel Sanz Merodio Electronic Physicist Director Dr. Elena Garcia Armada PhD Robotics and Automation, Industrial Engineer ESCUELA TECNICA SUPERIOR DE INGENIEROS INDUSTRIALES DEVELOPMENT OF STRATEGIES TO REDUCE ENERGY EXPENDITURE FOR LOWER-LIMB ACTIVE ORTHOSES DOCTORAL THESIS Daniel Sanz Merodio Electronic Physicist Director Dr. Elena Garcia Armada PhD Robotics and Automation, Industrial Engineer Madrid, September, 2018 Development of strategies to reduce energy expenditure for lower-limb active or- thoses Author: Daniel Sanz Merodio Advisor: Dr. Elena Garcia Armada First edition, August 2018 To Celsa, Gemma, Cecilia and Martina Abstract Lower-limb exoskeletons and powered orthoses are non-invasive devices that assist patients with locomotive disorders to achieve correct limb movements. The intended use as an assistive device for daily life activ- ities still encounters barriers to practical implementation. Current bat- teries cannot meet the long-term power requirements for these devices, which need to operate for long periods. This issue has become a ma- jor challenge in the development of these portable robots. Conversely, legged locomotion in animals and humans is efficient. This thesis ex- plores the methods to reduce energy consumption in the motion con- trol of gait exoskeletons and especially its applicability and feasibility. From a thorough analysis of the human gait from the energetic point of view and based on the state of development of robotics, a hybrid strategy is proposed to reduce energy consumption in the gait cycle. Three major research areas can be distinguished in energy-efficient biped walking robots: • The first research area focuses on developing optimal gait traject- ories for active walking robots. These trajectories are obtained by means of optimization procedures to minimize an objective function. • The second research area focuses on exploiting the passive-dynamics of the robot legs. In the first instance, the research is focused on non-active mechanisms that descend ramps taking advantage of the potential energy and the elastic energy of the ground contact. Subsequently, by applying these concepts, it is possible to make robots walk on flat ground providing only the amount of energy previously contributed by gravity, to take advantage of the elastic energy of the ground contact. • In the third area, leg dynamics is modified by including passive or active elastic mechanisms in the joints to reduce energy losses caused by the impact with the ground and to store and release energy for an improved energy-efficiency. In this thesis, a hybrid approach is proposed, taking advantage of the benefits of the above listed strategies to achieve an energy efficient gait. An hybrid approach is needed because gait exoskeletons applied to gait rehabilitation or assistance of people with neuromuscular dis- eases must respect the constraints imposed by the physiological needs of the patient. To solve this requirement the gait control approach must explode the natural dynamics of the leg; actively modifying joints dy- namics by the use of Variable Stiffness Actuators (VSA). By the application of a strategy of stiffness variation, control strategies based on passive dynamics can be implemented in the same joint, while the necessary torque can be provided by a stiff position controller in phases of higher torque demand, allowing subactuation in gait phases where inherent inertia is enough to take advantage of it and also provid- ing the high torque necessary for the orthosis to perform more versatile and non-cyclic movements, such as sitting and standing maneuvers. In turn, by establishing the adequate stiffness to the joint, energy con- sumption is reduced in changes of direction of the joint and energy can be stored and released in certain gait phases. The locomotion control strategies proposed have been validated through their implementation in the ATLAS active orthosis prototype. In this experiment, the importance of the variation of stiffness in relation to an efficient gait is reflected. This hybrid strategy achieves a reduction in energy consumption of 40%, while maintaining the robustness and reliability of the active orthosis with stiff actuators. The results of this research work have led to 7 publications in indexed scientific journals and 19 articles in international conferences, several of which have been awarded for their scientific and technical excel- lence. The doctoral thesis has had a relevant impact in the area of rehabilitation robotics since its results are being used in real environ- ments, since pediatric gait exoskeletons, transferred to the technology- based company Marsi Bionics, are being used in two hospitals in the therapy of neuromuscular diseases in childhood. Resumen El uso de las ortesis´ activas es cada vez mas´ habitual tanto en el campo de la rehabilitacion´ como asistencial. Las ortesis´ activas o exoesquele- tos de asistencia a la marcha humana son dispositivos de uso externo para pacientes con problemas de movilidad que aportan la fuerza y movilidad que le falta al usuario. El uso de estos dispositivos puede ser optimo´ utilizado a diario, integrado en el mayor numero´ de activida- des cotidianas posible. Pero las ortesis´ activas comerciales actuales no tienen autonom´ıa suficiente para proporcionar la potencia consumida durante toda una jornada. Las bater´ıas actuales no proporcionan los re- querimientos de potencia que demandan estas ortesis´ activas. Aumen- tar la autonom´ıa energetica´ se ha convertido en uno de los grandes retos para el desarrollo de estos estos dispositivos. En general, el consumo energetico´ de los robots b´ıpedos de uso general es significativamente mayor que el de los humanos u otros b´ıpedos mam´ıferos. A partir de un minucioso analisis´ de la marcha humana y la anatom´ıa de la loco- mocion´ desde el punto de vista energetico´ y basandose´ en el estado del arte de la robotica,´ en esta tesis se propone una estrategia h´ıbrida para reducir el consumo energetico´ en la marcha, primando la aplicabilidad y la fiabilidad para implementarla en el exoesqueleto ATLAS. En el campo de los robots b´ıpedos se distinguen fundamentalmente tres estrategias de eficiencia energetica:´ 1. Optimizar las trayectorias a seguir por el extremo de la pierna para minimizar una funcion´ objetivo relacionada con la energ´ıa consumida. 2. Aprovechar la dinamica´ pasiva (energ´ıa potencial y cinetica)´ de la pierna del robot para realizar el movimiento subactuado o con poca inyeccion´ de energ´ıa. 3. En el diseno˜ de la extremidad robotica,´ modificar su dinamica´ in- cluyendo elementos y mecanismos elasticos´ en las articulaciones para reducir las perdidas´ de energ´ıa en los impactos con el suelo y para acumular y soltar energ´ıa en las fases de la marcha donde el comportamiento energetico´ de las articulaciones sea el mismo que el de un elemento elastico.´ En esta tesis se propone una aproximacion´ h´ıbrida, que trata de aunar los beneficios de cada estrategia anterior. Habitualmente los pacientes objetivo, hacia los que esta´ enfocado el di- seno˜ de estos exoesqueletos, tienen l´ımites articulares importantes, fle- xos de cadera, rodilla y una marcada limitacion´ en el rango de flexion´ en el tobillo. As´ı, la primera estrategia presentada no es directamente aplicable, puesto que la trayectoria del extremo efectivo en las orte-´ sis activas debe calcularse respetando las restricciones anatomicas´ del paciente. La segunda y tercera estrategias planteadas se logran en esta tesis proponiendo e implementado un esquema de control de rigidez en un actuador de rigidez variable (VSA). Gracias a esta estrategia de variacion´ de rigidez se pueden implementar en una misma articulacion´ estrategias de control basadas en la dinami-´ ca pasiva en la marcha, mientras que se puede aportar el par necesario para un control r´ıgido en posicion´ en fases de mayor demanda de par, permitiendo as´ı subactuacion´ en fases de la marcha donde la inercia inherente al movimiento es suficiente para mantenerlo y tambien´ apor- tando el alto par necesario para que la ortesis´ realice movimientos mas´ versatiles´ y no c´ıclicos, como maniobras de sentar y levantar al pa- ciente. A su vez, estableciendo la rigidez adecuada a la articulacion,´ se reduce el consumo en los cambios de direccion´ de la articulacion´ y se puede almacenar y liberar energ´ıa en ciertas fases. Las estrategias de control de la locomocion´ propuestas se han validado a traves´ de su implementacion´ en el prototipo de ortesis´ activa ATLAS. En esta experimentacion´ se refleja la importancia de la variacion´ de rigidez en relacion´ con una marcha eficiente. Esta estrategia h´ıbrida logra una reduccion´ en el consumo energetico´ de 40 %, mientras se mantiene la robustez y fiabilidad de la ortesis´ activa con actuadores r´ıgidos. Los resultados del trabajo de investigacion´ han dado lugar a siete pu- blicaciones en revistas cient´ıficas indexadas y 19 art´ıculos en congre- sos internacionales, varios de los cuales han sido premiados por su excelencia cient´ıfica y tecnica.´ La tesis doctoral ha tenido un impacto relevante en el area´ de la robotica´ de rehabilitacion´ ya que sus resulta- dos estan´ utilizandose´ en entornos reales, dado que los exoesqueletos de marcha pediatricos,´ transferidos a la empresa de base tecnologica´ Marsi Bionics, estan´ siendo utilizados en dos hospitales del pa´ıs en la terapia de enfermedades neuromusculares en la infancia. Acknowledgements I would like to begin by giving thanks the Centre for Automation and Robotics UPM-CSIC in which this thesis was carried out. I also wish to thank my research adviser, Dr. Elena Garcia for her dir- ection, suggestions, patience, advice and the opportunity and privilege of working in this project. My gratitude also extends to my coworkers (Juan Carlos, Manuel, Xavi, Luis, Leonel, Mariano, etc.) for their dedication, advises, help and good moments that we have labored together in the past years on common work.
Recommended publications
  • Potential Energyenergy Isis Storedstored Energyenergy Duedue Toto Anan Objectobject Location.Location
    TypesTypes ofof EnergyEnergy && EnergyEnergy TransferTransfer HeatHeat (Thermal)(Thermal) EnergyEnergy HeatHeat (Thermal)(Thermal) EnergyEnergy . HeatHeat energyenergy isis thethe transfertransfer ofof thermalthermal energy.energy. AsAs heatheat energyenergy isis addedadded toto aa substances,substances, thethe temperaturetemperature goesgoes up.up. MaterialMaterial thatthat isis burning,burning, thethe Sun,Sun, andand electricityelectricity areare sourcessources ofof heatheat energy.energy. HeatHeat (Thermal)(Thermal) EnergyEnergy Thermal Energy Explained - Study.com SolarSolar EnergyEnergy SolarSolar EnergyEnergy . SolarSolar energyenergy isis thethe energyenergy fromfrom thethe Sun,Sun, whichwhich providesprovides heatheat andand lightlight energyenergy forfor Earth.Earth. SolarSolar cellscells cancan bebe usedused toto convertconvert solarsolar energyenergy toto electricalelectrical energy.energy. GreenGreen plantsplants useuse solarsolar energyenergy duringduring photosynthesis.photosynthesis. MostMost ofof thethe energyenergy onon thethe EarthEarth camecame fromfrom thethe Sun.Sun. SolarSolar EnergyEnergy Solar Energy - Defined and Explained - Study.com ChemicalChemical (Potential)(Potential) EnergyEnergy ChemicalChemical (Potential)(Potential) EnergyEnergy . ChemicalChemical energyenergy isis energyenergy storedstored inin mattermatter inin chemicalchemical bonds.bonds. ChemicalChemical energyenergy cancan bebe released,released, forfor example,example, inin batteriesbatteries oror food.food. ChemicalChemical (Potential)(Potential)
    [Show full text]
  • An Overview on Principles for Energy Efficient Robot Locomotion
    REVIEW published: 11 December 2018 doi: 10.3389/frobt.2018.00129 An Overview on Principles for Energy Efficient Robot Locomotion Navvab Kashiri 1*, Andy Abate 2, Sabrina J. Abram 3, Alin Albu-Schaffer 4, Patrick J. Clary 2, Monica Daley 5, Salman Faraji 6, Raphael Furnemont 7, Manolo Garabini 8, Hartmut Geyer 9, Alena M. Grabowski 10, Jonathan Hurst 2, Jorn Malzahn 1, Glenn Mathijssen 7, David Remy 11, Wesley Roozing 1, Mohammad Shahbazi 1, Surabhi N. Simha 3, Jae-Bok Song 12, Nils Smit-Anseeuw 11, Stefano Stramigioli 13, Bram Vanderborght 7, Yevgeniy Yesilevskiy 11 and Nikos Tsagarakis 1 1 Humanoids and Human Centred Mechatronics Lab, Department of Advanced Robotics, Istituto Italiano di Tecnologia, Genova, Italy, 2 Dynamic Robotics Laboratory, School of MIME, Oregon State University, Corvallis, OR, United States, 3 Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, 4 Robotics and Mechatronics Center, German Aerospace Center, Oberpfaffenhofen, Germany, 5 Structure and Motion Laboratory, Royal Veterinary College, Hertfordshire, United Kingdom, 6 Biorobotics Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 7 Robotics and Multibody Mechanics Research Group, Department of Mechanical Engineering, Vrije Universiteit Brussel and Flanders Make, Brussels, Belgium, 8 Centro di Ricerca “Enrico Piaggio”, University of Pisa, Pisa, Italy, 9 Robotics Institute, Carnegie Mellon University, Pittsburgh, PA, United States, 10 Applied Biomechanics Lab, Department of Integrative Physiology,
    [Show full text]
  • UNIVERSITY of CALIFONIA SANTA CRUZ HIGH TEMPERATURE EXPERIMENTAL CHARACTERIZATION of MICROSCALE THERMOELECTRIC EFFECTS a Dissert
    UNIVERSITY OF CALIFONIA SANTA CRUZ HIGH TEMPERATURE EXPERIMENTAL CHARACTERIZATION OF MICROSCALE THERMOELECTRIC EFFECTS A dissertation submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in ELECTRICAL ENGINEERING by Tela Favaloro September 2014 The Dissertation of Tela Favaloro is approved: Professor Ali Shakouri, Chair Professor Joel Kubby Professor Nobuhiko Kobayashi Tyrus Miller Vice Provost and Dean of Graduate Studies Copyright © by Tela Favaloro 2014 This work is licensed under a Creative Commons Attribution- NonCommercial-NoDerivatives 4.0 International License Table of Contents List of Figures ............................................................................................................................ vi List of Tables ........................................................................................................................... xiv Nomenclature .......................................................................................................................... xv Abstract ................................................................................................................................. xviii Acknowledgements and Collaborations ................................................................................. xxi Chapter 1 Introduction .......................................................................................................... 1 1.1 Applications of thermoelectric devices for energy conversion ................................... 1
    [Show full text]
  • Benefits and Challenges of Mechanical Spring Systems for Energy Storage Applications
    Available online at www.sciencedirect.com ScienceDirect Energy Procedia 82 ( 2015 ) 805 – 810 ATI 2015 - 70th Conference of the ATI Engineering Association Benefits and challenges of mechanical spring systems for energy storage applications Federico Rossia, Beatrice Castellania*, Andrea Nicolinia aUniversity of Perugia, Department of Engineering, CIRIAF, Via G. Duranti 67, Perugia Abstract Storing the excess mechanical or electrical energy to use it at high demand time has great importance for applications at every scale because of irregularities of demand and supply. Energy storage in elastic deformations in the mechanical domain offers an alternative to the electrical, electrochemical, chemical, and thermal energy storage approaches studied in the recent years. The present paper aims at giving an overview of mechanical spring systems’ potential for energy storage applications. Part of the appeal of elastic energy storage is its ability to discharge quickly, enabling high power densities. This available amount of stored energy may be delivered not only to mechanical loads, but also to systems that convert it to drive an electrical load. Mechanical spring systems’ benefits and limits for storing macroscopic amounts of energy will be assessed and their integration with mechanical and electrical power devices will be discussed. ©© 2015 2015 The The Authors. Authors. Published Published by Elsevier by Elsevier Ltd. This Ltd. is an open access article under the CC BY-NC-ND license (Selectionhttp://creativecommons.org/licenses/by-nc-nd/4.0/ and/or peer-review under responsibility). of ATI Peer-review under responsibility of the Scientific Committee of ATI 2015 Keywords:energy storage; mechanical springs; energy storage density. 1.
    [Show full text]
  • Preliminary Program
    2019 Knowledge Without Borders PRELIMINARY PROGRAM Combined AACPDM 73rd Annual and IAACD 2nd Triannual Meeting SEPTEMBER 18–21, 2019 ANAHEIM, CALIFORNIA USA 2018-2019 BOARD OF DIRECTORS PRESIDENT Jilda Vargus-Adams, MD, MSc Cincinnati Children’s Hospital Medical Center Cincinnati, OH FIRST VICE PRESIDENT Mauricio Delgado, MD Texas Scottish Rite Hospital for Children Dallas, TX SECOND VICE PRESIDENT We are excited to welcome you to Anaheim for the combined 73rd American Academy Susan Sienko, PhD for Cerebral Palsy and Developmental Medicine (AACPDM) Annual and 2nd Triannual Shriners Hospitals for Children International Alliance of Academies of Childhood Disability (IAACD) Meeting. The Portland, OR theme for the meeting is “Knowledge without Borders” which is an invitation to think TREASURER outside of the box so we can come up with new problem-solving approaches through Sylvia Õunpuu, MSc collective creativity and innovation. Each year the annual meeting provides the Connecticut Children’s Medical Center Academy the opportunity to showcase its mission and to fulfill its vision; namely, to be Farmington, CT a global leader in the multidisciplinary scientific education of health professionals and TREASURER-ELECT researchers dedicated to the well-being of people with and at risk for cerebral palsy Francisco Valencia, MD and other childhood-onset disabilities. University Orthopedic Specialists The Scientific Program Committee, chaired by Dr. Veronica Schiariti and Dr. Francisco Tucson, AZ Valencia with IAACD Co-Chair Dr. Diane Damiano, put together an outstanding SECRETARY scientific program that represents the state-of-the-science in cerebral palsy and Uri Givon, MD other childhood-onset disabilities. The committee was challenged to select the 120 Safra Hospital for Children scientific papers and 283 scientific posters from near record-breaking number of Tel Hashomer, Israel quality submissions received for this year’s meeting.
    [Show full text]
  • Mechanical Energy
    Chapter 2 Mechanical Energy Mechanics is the branch of physics that deals with the motion of objects and the forces that affect that motion. Mechanical energy is similarly any form of energy that’s directly associated with motion or with a force. Kinetic energy is one form of mechanical energy. In this course we’ll also deal with two other types of mechanical energy: gravitational energy,associated with the force of gravity,and elastic energy, associated with the force exerted by a spring or some other object that is stretched or compressed. In this chapter I’ll introduce the formulas for all three types of mechanical energy,starting with gravitational energy. Gravitational Energy An object’s gravitational energy depends on how high it is,and also on its weight. Specifically,the gravitational energy is the product of weight times height: Gravitational energy = (weight) × (height). (2.1) For example,if you lift a brick two feet off the ground,you’ve given it twice as much gravitational energy as if you lift it only one foot,because of the greater height. On the other hand,a brick has more gravitational energy than a marble lifted to the same height,because of the brick’s greater weight. Weight,in the scientific sense of the word,is a measure of the force that gravity exerts on an object,pulling it downward. Equivalently,the weight of an object is the amount of force that you must exert to hold the object up,balancing the downward force of gravity. Weight is not the same thing as mass,which is a measure of the amount of “stuff” in an object.
    [Show full text]
  • Preliminary Program
    2019 Knowledge Without Borders PRELIMINARY PROGRAM Combined AACPDM 73rd Annual and IAACD 2nd Triannual Meeting SEPTEMBER 18–21, 2019 ANAHEIM, CALIFORNIA USA 2018-2019 BOARD OF DIRECTORS PRESIDENT Jilda Vargus-Adams, MD, MSc Cincinnati Children’s Hospital Medical Center Cincinnati, OH FIRST VICE PRESIDENT Mauricio Delgado, MD Texas Scottish Rite Hospital for Children Dallas, TX SECOND VICE PRESIDENT We are excited to welcome you to Anaheim for the combined 73rd American Academy Susan Sienko, PhD for Cerebral Palsy and Developmental Medicine (AACPDM) Annual and 2nd Triannual Shriners Hospitals for Children International Alliance of Academies of Childhood Disability (IAACD) Meeting. The Portland, OR theme for the meeting is “Knowledge without Borders” which is an invitation to think TREASURER outside of the box so we can come up with new problem-solving approaches through Sylvia Õunpuu, MSc collective creativity and innovation. Each year the annual meeting provides the Connecticut Children’s Medical Center Academy the opportunity to showcase its mission and to fulfill its vision; namely, to be Farmington, CT a global leader in the multidisciplinary scientific education of health professionals and TREASURER-ELECT researchers dedicated to the well-being of people with and at risk for cerebral palsy Francisco Valencia, MD and other childhood-onset disabilities. University Orthopedic Specialists The Scientific Program Committee, chaired by Dr. Veronica Schiariti and Dr. Francisco Tucson, AZ Valencia with IAACD Co-Chair Dr. Diane Damiano, put together an outstanding SECRETARY scientific program that represents the state-of-the-science in cerebral palsy and Uri Givon, MD other childhood-onset disabilities. The committee was challenged to select the 120 Safra Hospital for Children scientific papers and 283 scientific posters from near record-breaking number of Tel Hashomer, Israel quality submissions received for this year’s meeting.
    [Show full text]
  • Energy Dissipation Mechanism and Damage Model of Marble Failure Under Two Stress Paths
    L. Zhang et alii, Frattura ed Integrità Strutturale, 30 (2014) 515-525; DOI: 10.3221/IGF-ESIS.30.62 Energy dissipation mechanism and damage model of marble failure under two stress paths Liming Zhang College of Science, Qingdao Technological University, Qingdao, Shandong 266033, China; [email protected] Co-operative Innovation Center of Engineering Construction and Safety in Shandong Peninsula blue economic zone, Qingdao Technological University ; Qingdao, Shandong 266033, China; [email protected] Mingyuan Ren, Shaoqiong Ma, Zaiquan Wang College of Science, Qingdao Technological University, Qingdao, Shandong 266033, China; Email: [email protected], [email protected], [email protected] ABSTRACT. Marble conventional triaxial loading and unloading failure testing research is carried out to analyze the elastic strain energy and dissipated strain energy evolutionary characteristics of the marble deformation process. The study results show that the change rates of dissipated strain energy are essentially the same in compaction and elastic stages, while the change rate of dissipated strain energy in the plastic segment shows a linear increase, so that the maximum sharp point of the change rate of dissipated strain energy is the failure point. The change rate of dissipated strain energy will increase during unloading confining pressure, and a small sharp point of change rate of dissipated strain energy also appears at the unloading point. The damage variable is defined to analyze the change law of failure variable over strain. In the loading test, the damage variable growth rate is first rapid then slow as a gradual process, while in the unloading test, a sudden increase appears in the damage variable before reaching the rock peak strength.
    [Show full text]
  • Dissipation Potentials from Elastic Collapse
    Dissipation potentials from royalsocietypublishing.org/journal/rspa elastic collapse Joe Goddard1 and Ken Kamrin2 1Department of Mechanical and Aerospace Engineering, University Research of California, San Diego, CA, USA 2 Cite this article: Goddard J, Kamrin K. 2019 Department of Mechanical Engineering, Massachusetts Institute of Dissipation potentials from elastic collapse. Technology, Cambridge, MA, USA Proc.R.Soc.A475: 20190144. JG, 0000-0003-4181-4994 http://dx.doi.org/10.1098/rspa.2019.0144 Generalizing Maxwell’s (Maxwell 1867 IV. Phil. Trans. Received: 7 March 2019 R. Soc. Lond. 157, 49–88 (doi:10.1098/rstl.1867.0004)) classical formula, this paper shows how the Accepted: 9 May 2019 dissipation potentials for a dissipative system can be derived from the elastic potential of an elastic system Subject Areas: undergoing continual failure and recovery. Hence, stored elastic energy gives way to dissipated elastic mechanics energy. This continuum-level response is attributed broadly to dissipative microscopic transitions over Keywords: a multi-well potential energy landscape of a type dissipative systems, nonlinear Onsager studied in several previous works, dating from symmetry, elastic failure, energy landscape Prandtl’s (Prandtl 1928 Ein Gedankenmodell zur kinetischen Theorie der festen Körper. ZAMM 8, Author for correspondence: 85–106) model of plasticity. Such transitions are assumed to take place on a characteristic time scale Joe Goddard T, with a nonlinear viscous response that becomes a e-mail: [email protected] plastic response for T → 0. We consider both discrete mechanical systems and their continuum mechanical analogues, showing how the Reiner–Rivlin fluid arises from nonlinear isotropic elasticity. A brief discussion is given in the conclusions of the possible extensions to other dissipative processes.
    [Show full text]
  • Proceedings of the 3Rd International Mobile Brain/Body Imaging Conference Berlin, July 12Th to July 14Th 2018
    Proceedings of the 3rd International Mobile Brain/Body Imaging Conference Berlin, July 12th to July 14th 2018 Edited by Prof. Dr. Klaus Gramann Technische Universität Berlin Department of Psychology and Ergonomics Chair Biological Psychology and Neuroergonomics This work is licensed under a Creative Commons License. License: Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ Published on the repository of TU Berlin DepositOnce DOI 10.14279/depositonce-7236 https://doi.org/10.14279/depositonce-7236 Conference Proceedings of the 3rd International Mobile Brain/Body Imaging Conference Berlin, July 12th to July 14th 2018 The 3rd International Mobile Brain/Body Imaging Conference was supported by: The German Research Foundation DFG (Grant GR2627/10-1) The National Science Foundation NSF (Grant NSF CBET-1757760) The Office of Naval Research Global ONRG (Grant N62909-16-1-2065) 2 Conference Proceedings of the 3rd International Mobile Brain/Body Imaging Conference Berlin, July 12th to July 14th 2018 Table of Contents Keynotes ...................................................................................................................... 11 MoBI for investigating disordered motor control in children with cerebral palsy ............ 11 Diane Damiano ............................................................................................................. 11 Exercise your Brain and Mind ....................................................................................... 11 Art Kramer ....................................................................................................................
    [Show full text]
  • The Relationship Between Energy Demand and Real GDP Growth Rate: the Role of Price Asymmetries and Spatial Externalities Within 34 Countries Across the Globe
    The relationship between energy demand and real GDP growth rate: the role of price asymmetries and spatial externalities within 34 countries across the globe Panagiotis Fotis a Hellenic Competition Commission Commissioner Sotiris Karkalakos b University of Piraeus and DePaul University Department of Economics Dimitrios Asteriou c Oxford Brookes University Department of Accounting, Finance and Economics Abstract The aim of this paper is to empirically explore the relationship between energy demand and real Gross Domestic Product (GDP) growth and to investigate the role of asymmetries (price and GDP growth asymmetries) and regional externalities on Final Energy Consumption (FEC ) in 34 countries during the period from 2005 to 2013. The paper utilizes a Panel Generalized Method of Moments approach in order to analyse the effect of real GDP growth rate on FEC through an Error Correction Model (ECM) and spatial econometric techniques in order to examine clustered patterns of energy consumption. The results show that a) the demand is elastic both in the industrial and the household/services sectors, b) electricity and natural gas are demand substitutes, c) the relationship between real GDP growth rate and energy consumption exhibits an inverted U – shape, d) price (electricity and gas) and GDP growth asymmetries are supported from the employed parametric and non – parametric tests, and e) distance does not affect FEC, but economic neighbors have a strong positive effect. Keywords: energy demand; dynamic panel data; error correction model; spatial externalities. JEL classification C21; C23; C51; L16; R12 a Corresponding Author , Hellenic Competition Commission, Commissionner, 5 P. Ioakim St., 12132, Peristeri, Greece, Tel.: +30 6947609741, E-mail: [email protected] .
    [Show full text]
  • Energy Regenerative Damping in Variable Impedance Actuators for Long-Term Robotic Deployment
    XXXX, VOL. X, NO. X, JANUARY 2020 1 Energy regenerative damping in variable impedance actuators for long-term robotic deployment Fan Wu and Matthew Howard∗† Abstract—Energy efficiency is a crucial issue towards long- Recently, much research effort has gone into the design term deployment of compliant robots in the real world. In of variable physical damping actuation, based on different the context of variable impedance actuators (VIAs), one of the principles of damping force generation (see [4], [5] for a main focuses has been on improving energy efficiency through reduction of energy consumption. However, the harvesting of review). Variable physical damping has proven to be necessary dissipated energy in such systems remains under-explored. This to achieve better task performance, for example, in eliminat- study proposes a variable damping module design enabling ing undesired oscillations caused by the elastic elements of energy regeneration in VIAs by exploiting the regenerative VSAs [6], [7]. It has also been demonstrated that variable braking effect of DC motors. The proposed damping module physical damping plays an important role in terms of energy uses four switches to combine regenerative and dynamic braking, in a hybrid approach that enables energy regeneration without efficiency for actuators that are required to operate at different a reduction in the range of damping achievable. A physical frequencies, to optimally exploit the natural dynamics [6]. implementation on a simple VIA mechanism is presented in However, while these studies represent important advances which the regenerative properties of the proposed module are in terms of improving the efficiency of energy consumption characterised and compared against theoretical predictions.
    [Show full text]