Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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Now showing 1 - 10 of 18
  • Publication
    PowerGrasp: Development Aspects for Arm Support Systems
    ( 2022)
    Goppold, J.-P.
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    Kuschan, J.
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    Schmidt, H.
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    Krüger, J.
    Exoskeletons can support workers on physically demanding tasks, but in industry they lack of acceptance. This contribution gives an insight into design aspects for upper body exoskeletons, especially how active exoskeletons for industrial applications differ from military and medical use-cases. To overcome typical rigid exoskeleton problems, we suggest the use of modular soft-exosuit support systems and therefore checked different types of soft actuation principles for their eligibility for the use on upper body joints. Most promising approach is using two-layered actuators sting of robust fabric with embedded rubber tubes as pressure chambers. By inflating the tubes, it is possible to vary the stiffness of the chambers, which can be effectively used to generate assisting forces and moments at human joints (shoulder, elbow, wrist, finger).
  • Publication
    User-centered design of a patient's work station for haptic robot-based telerehabilitation after stroke
    ( 2017)
    Ivanova, E.
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    Minge, M.
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    Schmidt, H.
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    Thüring, M.
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    Krüger, J.
    Robotic therapy devices have been an important part of clinical neurological rehabilitation for several years. Until now such devices are only available for patients receiving therapy inside rehabilitation hospitals. Since patients should continue rehabilitation training after hospital discharge at home, intelligent robotic rehab devices could help to achieve this goal. This paper presents therapeutic requirements and early phases of the user-centered design process of the patient's work station as part of a novel robot-based system for motor telerehabilitation.
  • Publication
    Let's do this together: Bi-Manu-Interact, a novel device for studying human haptic interactive behavior
    ( 2017)
    Ivanova, E.
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    Krause, A.
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    Schälicke, M.
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    Schellhardt, F.
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    Jankowski, N.
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    Achner, J.
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    Schmidt, H.
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    Joebges, M.
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    Krüger, J.
    Our area of interest is robotic-based rehabilitation after stroke, and our goal is to help patients achieve optimal motor learning during high-intensity repetitive movement training through the assistance of robots. It is important, that the robotic assistance is adapted to the patients' abilities, thereby ensuring that the device is only supporting the patient as necessary ('assist-as-needed'). We hypothesize that natural and learning-effective human-machine interaction can be achieved by programming the robot's control, so that it emulates how a physiotherapist adaptively supports the patients' limb movement during stroke rehabilitation. This paper introduces the design of a novel interactive device Bi-Manu-Interact. This device is suited to be used as an experimental setup for the investigation of haptic human-human interaction and for collecting data to model therapists' haptic behavior. In this paper, we present mechanical and sensory specifications as well as task s visualizations for future investigations. Results of a pilot clinical evaluation of the Bi-Manu-Interact with nine stroke patients are also presented in this work.
  • Publication
    Design of a pressure sensitive matrix for analyzing direct haptic patient-therapist interaction in motor rehabilitation after stroke
    ( 2017)
    Pust, M.
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    Ivanova, E.
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    Schmidt, H.
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    Krüger, J.
    Robot based therapy is one of the prevalent therapeutic approaches in motor stroke rehabilitation. It is often used in hospitals in combination with conventional therapy. In order to optimize human-robot interaction, we aim to investigate how a therapist physically supports patients during motor training of the upper extremities. This paper presents the design of a flexible textile sensor matrix, which measures the pressure exerted between therapist and patient during direct haptic interaction as well as the hand position and orientation in space. The matrix contains 144 sensors which enables measuring pressure intensity and localization of areas where the pressure is applied. The measurement matrix was evaluated with four healthy participants.
  • Publication
    Computerised mirror therapy with Augmented Reflection Technology for early stroke rehabilitation
    ( 2017)
    Hoermann, S.
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    Santos, L.F. dos
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    Morkisch, N.
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    Jettkowski, K.
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    Sillis, M.
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    Devan, H.
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    Kanagasabai, P.S.
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    Schmidt, H.
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    Krüger, J.
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    Dohle, C.
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    Regenbrecht, H.
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    Hale, L.
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    Cutfield, N.J.
    Purpose: New rehabilitation strategies for post-stroke upper limb rehabilitation employing visual stimulation show promising results, however, cost-efficient and clinically feasible ways to provide these interventions are still lacking. An integral step is to translate recent technological advances, such as in virtual and augmented reality, into therapeutic practice to improve outcomes for patients. This requires research on the adaptation of the technology for clinical use as well as on the appropriate guidelines and protocols for sustainable integration into therapeutic routines. Here, we present and evaluate a novel and affordable augmented reality system (Augmented Reflection Technology, ART) in combination with a validated mirror therapy protocol for upper limb rehabilitation after stroke. Method: We evaluated components of the therapeutic intervention, from the patients' and the therapists' points of view in a clinical feasibility study at a rehabilitation centre. We also assessed the integration of ART as an adjunct therapy for the clinical rehabilitation of subacute patients at two different hospitals. Results: The results showed that the combination and application of the Berlin Protocol for Mirror Therapy together with ART was feasible for clinical use. This combination was integrated into the therapeutic plan of subacute stroke patients at the two clinical locations where the second part of this research was conducted. Conclusions: Our findings pave the way for using technology to provide mirror therapy in clinical settings and show potential for the more effective use of inpatient time and enhanced recoveries for patients.
  • Publication
    Optimal torque adaptation in bimanual assisted rehabilitation
    ( 2012)
    Steingräber, R.
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    Schmidt, H.
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    Krüger, J.
  • Publication
    Visuelles Biofeedback für die gerätegestützte neurologische Gangrehabilitation nach Schlaganfall
    ( 2010)
    Brüning, M.
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    Hussein, S.
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    Bardeleben, A.
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    Schmidt, H.
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    Krüger, J.
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    Hesse, S.
  • Publication
    Richtlinien für die Gestaltung von visuellem Biofeedback in der neurologischen Gangrehabilitation nach Schlaganfall
    ( 2010)
    Brüning, M.
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    Hussein, S.
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    Bardeleben, A.
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    Schmidt, H.
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    Krüger, J.
    ;
    Hesse, S.
  • Publication
    Structural analysis method for optimized design of complex kinematic structures using static and dynamic models and application to a robotic walking simulator
    ( 2010)
    Brüning, M.
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    Hussein, S.
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    Schmidt, H.
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    Krüger, J.
    This paper describes an approach for structural analysis for design improvements of complex, e.g. hybrid, kinematic structures utilizing static and dynamic models. It is suitable to locate improvement potentials in existing mechanisms, facilitate goal-oriented design of new mechanisms or for a simulation-based controller synthesis e.g. a compliance-controller. To receive a model close to reality, mechanical influences, which are commonly neglected in conventional robot models, are analyzed regarding their relevance and if suitable integrated into the model. Investigated effects are the mechanical compliances of links and gears, compliances of the actuators resulting from the control circuits as well as non-linear frictional influences of the actuators. The kinematic and dynamic model is realized as an iterative solution instead of a closed analytic solution with extensive symbolic expressions. This leads to an analysis with clearly arranged aspects, further more the model is suitable for usage in a real-time control. The mechanical influences are analyzed analytically. The derived dynamic modeling is based on the Newton-Euler formulation. The approach is applied to the robotic walking simulator HapticWalker, a device for robot assisted gait rehabilitation. It consists of two identical hybrid parallel-serial manipulators. The forces calculated by the use of the developed model are in a good congruence with measured values. An obviously improved correspondence between measured and calculated values is achieved by the non-linear friction model of the actuators.
  • Publication
    Effect of different training modes on ground reaction forces during robot assisted floor walking and stair climbing
    ( 2009)
    Hussein, S.
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    Schmidt, H.
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    Hesse, S.
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    Krüger, J.
    The HapticWalker is a robotic walking simulator for neurological gait rehabilitation. The device is based on the end-effector principle, i.e. the patients' feet are fixed on two footplates, his trunk is secured via a suspension harness. The footplates (end-effectors) of the robot guide the feet of the patient on freely programmable trajectories. Currently two different training modes are provided for each foot trajectory on the HapticWalker. Firstly training trajectories based on real motion capture data can be used. Secondly the vertical center of mass (CoM) motion can be incorporated into the foot trajectory. The latter method leaves the absolute position of the CoM constant, while the relative movement between CoM and feet remains the same as in free walking. Thereby the v ertical CoM motion can be actively supported by using a fixed passive suspension, any type of controlled body weight support will then be accomplished via force controlled footplates. To characterize the training on the machine in position controlled mode, muscle activities as well as ground reaction force data of healthy subjects were collected. This article presents preliminary results from the investigation of ground reaction force data of healthy subjects. Therefore data of 10 healthy subjects was used to compare HapticWalker training modes vs. free walking on level ground and upstairs without any assistive devices and the aforementioned two HapticWalker training modes against each other. Amplitude and timing of force peaks during heel strike, foot flat and push off in vertical ground reaction forces were used for the assessment. In spite of a footplate, which does not provide a separate metatarsal joint for relative motion between fore and hind foot, during heel strike and push off the known characteristic peaks at the beginning and the end of the stance phase can be clearly distinguished. Though compared to free walking a slower and premature rise and slower decline of ground reaction for- ces can be seen due to the stiff guidance of the feet in position controlled mode. No significant differences appeared between the two described HapticWalker training modes.