422 research outputs found

    ARMin: a robot for patient-cooperative arm therapy

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    Task-oriented, repetitive and intensive arm training can enhance arm rehabilitation in patients with paralyzed upper extremities due to lesions of the central nervous system. There is evidence that the training duration is a key factor for the therapy progress. Robot-supported therapy can improve the rehabilitation allowing more intensive training. This paper presents the kinematics, the control and the therapy modes of the arm therapy robot ARMin. It is a haptic display with semi-exoskeleton kinematics with four active and two passive degrees of freedom. Equipped with position, force and torque sensors the device can deliver patient-cooperative arm therapy taking into account the activity of the patient and supporting him/her only as much as needed. The haptic display is combined with an audiovisual display that is used to present the movement and the movement task to the patient. It is assumed that the patient-cooperative therapy approach combined with a multimodal display can increase the patient's motivation and activity and, therefore, the therapeutic progres

    Mutual interferences and design principles for mechatronic devices in magnetic resonance imaging

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    Purpose: Robotic and mechatronic devices that work compatibly with magnetic resonance imaging (MRI) are applied in diagnostic MRI, image-guided surgery, neurorehabilitation and neuroscience. MRI-compatible mechatronic systems must address the challenges imposed by the scanner's electromagnetic fields. We have developed objective quantitative evaluation criteria for device characteristics needed to formulate design guidelines that ensure MRI-compatibility based on safety, device functionality and image quality. Methods: The mutual interferences between an MRI system and mechatronic devices working in its vicinity are modeled and tested. For each interference, the involved components are listed, and a numerical measure for "MRI-compatibility” is proposed. These interferences are categorized into an MRI-compatibility matrix, with each element representing possible interactions between one part of the mechatronic system and one component of the electromagnetic fields. Based on this formulation, design principles for MRI-compatible mechatronic systems are proposed. Furthermore, test methods are developed to examine whether a mechatronic device indeed works without interferences within an MRI system. Finally, the proposed MRI-compatibility criteria and design guidelines have been applied to an actual design process that has been validated by the test procedures. Results: Objective and quantitative MRI-compatibility measures for mechatronic and robotic devices have been established. Applying the proposed design principles, potential problems in safety, device functionality and image quality can be considered in the design phase to ensure that the mechatronic system will fulfill the MRI-compatibility criteria. Conclusion: New guidelines and test procedures for MRI instrument compatibility provide a rational basis for design and evaluation of mechatronic devices in various MRI applications. Designers can apply these criteria and use the tests, so that MRI-compatibility results can accrue to build an experiential databas

    Das Fortpflanzungsverhalten der Breitrandschildkröte Testudo marginata Schoepff, 1792, in menschlicher Obhut

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    Im Zeitraum von 1997 bis 2008 wurden drei ausgewachsene Paare der Breitrandschildkröte Testudo marginata Schoepff, 1792, unter möglichst naturnahen Bedingungen in Österreich gehalten

    Langzeitstudie zum Fortpflanzungsverhalten von Testudo hermanni boettgeri und Testudo marginata

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    Im Zeitraum von 1997 bis 2011 wurde eine Langzeitstudie zur Reproduktion von Landschildkröten durchgeführt. Dabei wurde je eine Gruppe der östlichen Unterart der Griechischen Landschildkröte, T. h. boettgeri, und der Breitrandschildkröte, T. marginata, unter identischen und möglichst naturnahen Bedingungen in Österreich gehalten und vermehrt. Besonderes Augenmerk wurde hierbei auf die das weibliche Fortpflanzungsverhalten betreffenden Aspekte gelegt. Über den gesamten Beobachtungszeitraum von 15 Jahren ergaben sich sowohl Übereinstimmungen als auch deutliche Unterschiede in der Fortpflanzung aller beobachteten Weibchen, sowohl innerhalb der jeweiligen Art als auch zwischen den beiden Arten. Es wurden jedes Jahr in der Regel zwei Gelege pro Weibchen abgesetzt, oftmals konnten jedoch auch Drittgelege beobachtet werden. Die Ablagen erfolgten ausschließlich in den Monaten Mai, Juni und Juli. Bis auf einige einzelne verspätete Ablagen erwiesen sich alle Weibchen als sehr konstant, was die Ablagezeitpunkte und –Zeiträume betrifft. In manchen Jahren, bedingt durch außergewöhnliche klimatische Umstände, zeigte sich, dass Wetterlagen einen deutlichen Einfluss auf die Eiablagezeitpunkte haben. Aus der Auswertung der Daten zur Eiablage wie Datum, Eizahl, Anzahl der Erst-, Zweit- und Drittgelege etc., sowie Daten zum Schlupferfolg der einzelnen Weibchen, ergaben sich wichtige Erkenntnisse zu langfristigen Fortpflanzungsparametern wie beispielsweise Gelegegröße, Gelegeanzahl und Schlupfraten und wurden sowohl im Gesamten als auch auf jedes einzelne Individuum bezogen ermittelt sowie im Verlauf der Jahre erfasst. Signifikante. Unterschiede ergaben sich unter anderem in der Anzahl der Gelege pro Jahr, der Anzahl der Eier pro Gelege oder der Fruchtbarkeit bzw. des Schlupferfolges der Gelege. Die Arbeit gliedert sich in drei Hauptabschnitte, wobei in den ersten beiden die jeweilige Art im Speziellen behandelt wird und im dritten Teil die Ergebnisse der beiden angesprochenen Arten zueinander in Relation gesetzt werden, um etwaige Parallelen bzw. Abweichungen im Fortpflanzungsverhalten und Reproduktionserfolg der teilweise sympatrisch vorkommenden Schildkrötenarten darzustellen. Die Veranschaulichung erfolgt mittels Tabellen und graphischer Darstellung. Statistische Methoden fanden Anwendung.This study was conducted between 1997 and 2011. Groups of adult Herman`s Tortoise, T. h. boettgeri, and Marginated Tortoise, T. marginata, were kept and bred in Austria under near natural conditions. Special attention was paid to the female reproductive behaviour showing distinct differences, as well as similarities, between the observed female individuals. Over the entire 15 year period clear differences and correlations in reproduction for all fe-males was observed within individuals of the respective species as well as between both species. Important data regarding laying of eggs such as date, number of eggs, the number of first, second and third clutches as well as the hatching success of clutches from the individual females to long-term reproductive parameters such as clutch size, number of clutches and hatching rates were determined on the entire population as well as for every individual. Sig-nificant differences existed in the number of the clutches per year, the number of the eggs per clutch and of the hatching success of the clutches. The deployment of the clutches was limited to the months of May, June and July of which the majority were laid in May and June. This observation also correlates to the specifications of other literature for both captive and free land observations. Apart from a few single delays in clutch deployment all three females laid reliably regarding the deployment time and months of deployment, varying only slightly depending on the current weather conditions. In some years for example deployment shifted forward or backward up to two weeks due to weather conditions. The study consists of three major parts. In part one and two the respective species are ex-amined and in the third the results of both species are put in relation to each other in order to show divergence or parallels in the reproductive behavior and reproduction success of the two species. Illustration of our data is achieved by means of tables and graphic representation. Analytical Statistical methods were applied to further verify our findings

    Augmented visual, auditory, haptic, and multimodal feedback in motor learning: A review

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    It is generally accepted that augmented feedback, provided by a human expert or a technical display, effectively enhances motor learning. However, discussion of the way to most effectively provide augmented feedback has been controversial. Related studies have focused primarily on simple or artificial tasks enhanced by visual feedback. Recently, technical advances have made it possible also to investigate more complex, realistic motor tasks and to implement not only visual, but also auditory, haptic, or multimodal augmented feedback. The aim of this review is to address the potential of augmented unimodal and multimodal feedback in the framework of motor learning theories. The review addresses the reasons for the different impacts of feedback strategies within or between the visual, auditory, and haptic modalities and the challenges that need to be overcome to provide appropriate feedback in these modalities, either in isolation or in combination. Accordingly, the design criteria for successful visual, auditory, haptic, and multimodal feedback are elaborate

    Comfort of two shoulder actuation mechanisms for arm therapy exoskeletons: a comparative study in healthy subjects

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    Robotic exoskeletons can be used to study and treat patients with neurological impairments. They can guide and support the human limb over a large range of motion, which requires that the movement trajectory of the exoskeleton coincide with the one of the human arm. This is straightforward to achieve for rather simple joints like the elbow, but very challenging for complex joints like the human shoulder, which is comprised by several bones and can exhibit a movement with multiple rotational and translational degrees of freedom. Thus, several research groups have developed different shoulder actuation mechanism. However, there are no experimental studies that directly compare the comfort of two different shoulder actuation mechanisms. In this study, the comfort and the naturalness of the new shoulder actuation mechanism of the ARMin III exoskeleton are compared to a ball-and-socket-type shoulder actuation. The study was conducted in 20 healthy subjects using questionnaires and 3D-motion records to assess comfort and naturalness. The results indicate that the new shoulder actuation is slightly better than a ball-and-socket-type actuation. However, the differences are small, and under the tested conditions, the comfort and the naturalness of the two tested shoulder actuations do not differ a lo

    Benefits of Crank Moment Sonification in Cycling

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    AbstractIn sports, the provision of augmented feedback is an important means to accelerate learning of new movements. Traditionally, concurrent augmented feedback has been provided verbally or visually. However, more recent studies have shown sonification of data during the movement, i.e. the mapping of a measured variable to parameter of sound, can be very effective to learn temporal aspects of a movement or movement patterns. In this pilot study, it was investigated if learning of complex pushing-pulling action applied to clipless pedals of a cycling ergometer can be enhanced by sonification of the crank moment. Three novice and three experienced cyclists were invited to train a reference crank moment pattern for two consecutive days (a total of twelve training sessions of 60 s each). However, in contrast to the results found in studies on rowing, the applied sonification did not enhance learning compared to visual and verbal instruction only. The lack of learning might be due to an inappropriate sonification design, short training sessions or the high task complexity. Extended studies are needed to draw more significant conclusions

    Adaptive PatientenunterstĂĽtzung fĂĽr Rehabilitationsroboter

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    Rehabilitationsroboter unterstützen die Rehabilitation von Patienten mit Bewegungsstörungen aufgrund von Schädigungen des Nervensystems. Neu entwickelte, patientenkooperative Regelungsansätze sollen es diesen Robotern ermöglichen, individuell an die Patienten angepasste, effektivere Trainingseinheiten durchzuführen, als dies bislang möglich war. Dieser Beitrag beschreibt zwei Ansätze zur automatischen Anpassung der Roboterunterstützung: Die iterativ lernende Vorsteuerung ermöglicht die Unterstützung von Bewegungen mit definiertem zeitlichem Ablauf. Das iterativ lernende, konservative Kraftfeld ermöglicht die Unterstützung von Bewegungen mit freiem zeitlichem Ablauf. Das Verhalten beider Verfahren wird an einer Beispielanwendung mit dem Gang-Rehabilitationsroboter Lokomat demonstrier
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