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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improved design of three-degree of freedom hip exoskeleton based on biomimetic parallel structure

Pan, Min 01 July 2011 (has links)
The external skeletons, Exoskeletons, are not a new research area in this highly developed world. They are widely used in helping the wearer to enhance human strength, endurance, and speed while walking with them. Most exoskeletons are designed for the whole body and are powered due to their applications and high performance needs. This thesis introduces a novel design of a three-degree of freedom parallel robotic structured hip exoskeleton, which is quite different from these existing exoskeletons. An exoskeleton unit for walking typically is designed as a serial mechanism which is used for the entire leg or entire body. This thesis presents a design as a partial manipulator which is only for the hip. This has better advantages when it comes to marketing the product, these include: light weight, easy to wear, and low cost. Furthermore, most exoskeletons are designed for lower body are serial manipulators, which have large workspace because of their own volume and occupied space. This design introduced in this thesis is a parallel mechanism, which is more stable, stronger and more accurate. These advantages benefit the wearers who choose this product. This thesis focused on the analysis of the structure of this design, and verifies if the design has a reasonable and reliable structure. Therefore, a series of analysis has been done to support it. The mobility analysis and inverse kinematic solution are derived, and the Jacobian matrix was derived analytically. Performance of the CAD model has been checked by the finite element analysis in Ansys, which is based on applied force and moment. The comparison of the results from tests has been illustrated clearly for stability iii and practicability of this design. At the end of this thesis, an optimization of the hip exoskeleton is provided, which offers better structure of this design. / UOIT
2

Evaluation Of Impedance Control On A Powered Hip Exoskeleton

condoor, Punith 27 October 2017 (has links) (PDF)
This thesis presents an impedance control strategy for a novel powered hip exoskeleton designed to provide partial assistance and leverage the dynamics of human gait. The control strategy is based on impedance control and provides the user assistance as needed which is determined by the user’s interaction with the exoskeleton. A series elastic element is used to drive the exoskeleton and measures the interaction torque between the user and the device. The device operates in two modes. Free mode is a low impedance state that attempts to provide no assistance. Assist mode increases the gains of the controller to provide assistance as needed. The device was tested on five healthy subjects, and the resulting assistive hip torque was evaluated to determine the ability of the controller to provide gait assistance. The device was evaluated at different speeds to assess the gait speed adaptation performance of the controller. Results show that hip torque assistance range was between 0.3 to 0.5 Nm/kg across the subjects, corresponding to 24% to 40% of the maximum hip torque requirements of healthy adults during walking. The peak power provided by the system is 35 W on average and a peak power of up to 45 W.

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