Calibration of an EMG-Based Body Model with six Muscles to control a Leg Exoskeleton

Abstract — This paper presents a body model of intermediate level of detail to allow prediction of the knee torque produced by thigh muscles based on EMG signals. This torque prediction is used as input for a torque controller that adapts the level of support offered to an operator by a powered leg orthosis. The level of detail of the body model is chosen in such a way, that all parameters of the model can be calibrated for a specific operator with only a few sensors that are mounted on the exoskeleton. I

Framework for scenario development in LCA

This article is based on the work of the SETAC-Europe LCA Working Group ‘Scenario Development in LCA', which has started its work in April 1998. The goal of the Working Group is to focus on the use of scenarios in Life Cycle Assessment (LCA). This article presents the results of the first phase of the Working Group. The previous definitions of scenarios include three common basic elements: the definition of alternative future circumstances, the path from the present to the future, and the inclusion of uncertainty in the concept. We define a scenario in LCA as "a description of a possible future situation relevant for specific LCA applications, based on specific assumptions about the future, and (when relevant) also including the presentation of the development from the present to the future.' On the basis of the scenario definition we distinguish between two basic approaches for scenario development in LCA studies: What-if scenarios and Cornerstone scenarios. What-if scenarios are used to gain operational information and to compare two or more alternatives in a well-known situation with a short time horizon where the researcher is familiar with the decision problem and can set defined hypothesis on the basis of existing data. The Cornerstone scenario approach offers strategic information for long term planning, new ways of seeing the world, and also guidelines in the field of study. Results of a study using the Cornerstone scenario approach often serve as a basis for further, more specific research where the scenarios can be defined according to What-if scenarios. The frames of the scenarios are defined in the first phase of LCA, the goal and scope definition. Scenario development does, however, influence all of the following phases of LCA. The frames of the scenarios form the basis for modelling product systems and environmental impacts associated with products and services, which are not exactly known due to lacking information on parts of the life cycl

Searches at HERA for Squarks in R-Parity Violating Supersymmetry

A search for squarks in R-parity violating supersymmetry is performed in e^+p collisions at HERA at a centre of mass energy of 300 GeV, using H1 data corresponding to an integrated luminosity of 37 pb^(-1). The direct production of single squarks of any generation in positron-quark fusion via a Yukawa coupling lambda' is considered, taking into account R-parity violating and conserving decays of the squarks. No significant deviation from the Standard Model expectation is found. The results are interpreted in terms of constraints within the Minimal Supersymmetric Standard Model (MSSM), the constrained MSSM and the minimal Supergravity model, and their sensitivity to the model parameters is studied in detail. For a Yukawa coupling of electromagnetic strength, squark masses below 260 GeV are excluded at 95% confidence level in a large part of the parameter space. For a 100 times smaller coupling strength masses up to 182 GeV are excluded.Comment: 32 pages, 14 figures, 3 table

Multiplicity Structure of the Hadronic Final State in Diffractive Deep-Inelastic Scattering at HERA

The multiplicity structure of the hadronic system X produced in deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY vertex, t, is limited to |t|<1 GeV^2, is studied as a function of the invariant mass M_X of the system X. Results are presented on multiplicity distributions and multiplicity moments, rapidity spectra and forward-backward correlations in the centre-of-mass system of X. The data are compared to results in e+e- annihilation, fixed-target lepton-nucleon collisions, hadro-produced diffractive final states and to non-diffractive hadron-hadron collisions. The comparison suggests a production mechanism of virtual photon dissociation which involves a mixture of partonic states and a significant gluon content. The data are well described by a model, based on a QCD-Regge analysis of the diffractive structure function, which assumes a large hard gluonic component of the colourless exchange at low Q^2. A model with soft colour interactions is also successful.Comment: 22 pages, 4 figures, submitted to Eur. Phys. J., error in first submission - omitted bibliograph

Optics and Quantum Electronics

Contains table of contents on Section 3 and reports on nineteen research projects.Defense Advanced Research Projects Agency Grant F49620-96-0126Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant ECS 94-23737U.S. Air Force - Office of Scientific Research Contract F49620-95-1-0221U.S. Navy - Office of Naval Research Grant N00014-95-1-0715Defense Advanced Research Projects Agency/National Center for Integrated Photonics TechnologyMultidisciplinary Research InitiativeU.S. Air Force - Office of Scientific ResearchNational Science Foundation/MRSECU.S. Navy - Office of Naval Research (MFEL) Contract N00014-91-J-1956National Institutes of Health Grant R01-EY11289U.S. Navy - Office of Naval Research (MFEL) Contract N00014-94-0717Defense Advanced Research Projects Agency Contract N66001-96-C-863

Optics and Quantum Electronics

Contains table of contents for Section 3 and reports on eighteen research projects.Defense Advanced Research Projects Agency/MIT Lincoln Laboratory Contract MDA972-92-J-1038Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant ECS 94-23737U.S. Air Force - Office of Scientific Research Contract F49620-95-1-0221U.S. Navy - Office of Naval Research Grant N00014-95-1-0715MIT Center for Material Science and EngineeringNational Center for Integrated Photonics Technology Contract DMR 94-00334National Center for Integrated Photonics TechnologyU.S. Navy - Office of Naval Research (MFEL) Contract N00014-94-1-0717National Institutes of Health Grant 9-R01-EY11289MIT Lincoln Laboratory Contract BX-5098Electric Power Research Institute Contract RP3170-25ENEC

TORQUE CONTROL OF AN EXOSKELETAL KNEE WITH EMG SIGNALS

This paper introduces a control scheme and algorithm for a powered orthosis. Recognizing the intended motion is based on real-time evaluation of EMG signals recorded from the operator’s leg muscles. The desired motion is executed with a torque controller for an electric linear actuator. In contrast to most of the previous approaches for similar applications, this is performed without pattern classification and without a dynamic biomechanical model of the human body.

Aufwands- und ergebnisrelevante Probleme der Sachbilanzierung

Der Wunsch nach einer Gestaltung von zukünftiger gesellschaftlicher Entwicklung hat mit dem in den vergangenen Jahren entwickelten Leitbild Sustainable Development" eine starke Konkretisierung erfahren. Zwar ist die Vorstellung von dem, was unter Nachhaltiger Entwicklung heute verstanden wird, immer noch wage und an vielen Punkten verbesserungsfähig, dennoch sind ausgehend von den im Bericht der Brundlandt-Kommission 1988 formulierten Gedanken über die Ergebnisse der Konferenz der Vereinten Nationen über Umwelt und Entwicklung in Rio de Janeiro (1992) bis hin zur Konferenz über Nachhaltige Entwicklung in Johannesburg (2002) viele Fortschritte zu erkennen. An diesem Rio-Prozess sind zahlreiche Institutionen beteiligt, die aufganz unterschiedlichen Ebenen ihren Beitrag dazu leisten. Im Zusammenhang mit Nachhaltiger Entwicklung spielt die Bewertung von einzelnen Techniken und Produkten eine große Rolle. Immer wieder wird die Frage aufgeworfen, ob ein Produkt oder ein Konsummuster im Einklang mit nachhaltiger Entwicklung steht. Schnelle Antworten hierauf berühren meistens nur die Oberfläche und sind sehr oft falsch. Bei genauerer Prüfung stellt sich schnell heraus, dass für eine fundierte Antwort bereits die methodischen Grundlagen unvollständig sind, dass Daten nicht nach einheitlichen Vorschriften erhoben wurden oder dass Systemgrenzen nicht präzise genug formuliert wurden. Die Normenreihe DIN EN ISO 14040 ff. hat zwar einen ersten Rahmen für die Methode gesetzt, jedoch auf eine von vielen Aspekten abhängige Vorgehensweise verzichtet. Mit dem vorliegenden Bericht greifen die Autoren einen Teilaspekt dieses umfangreichen Themas auf, indem sie aufwands- und ergebnisrelevante Probleme der Sachbilanzierung genauer betrachten. Die Arbeiten präzisieren damit das methodische Fundament für die Ökobilanz (Life Cycle Assessment (LCA)). Der vorliegende Bericht ist das Ergebnis einer langjährigen Zusammenarbeit zwischen dem Institut für technischen Umweltschutz, Fachgebiet Abfallvermeidung und Sekundänohstoffwirtschaft (ASR), an der TU Berlin und der Programmgruppe Systemforschung und Technologische Entwicklung (STE) im Forschungszentrum Jülich . Die Autoren bedanken sich bei Dr. Petra Zapp, Dr. Robert Ackermann und Dr. Wilhelm Kuckshinrichs für die intensiven Sachdiskussionen und die kritischen Anregungen zum Manuskript