3 research outputs found
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Multi-fingered grasping and manipulation in virtual environments using an isometric finger device
In this article we present a new isometric input device for multi-fingered grasping in virtual environments. The device was designed to simultaneously assess forces applied by the thumb, index, and middle finger. A mathematical model of grasping, adopted from the analysis of multi-fingered robot hands, was applied to achieve multi-fingered interaction with virtual objects. We used the concept of visual haptic feedback where the user was presented with visual cues to acquire haptic information from the virtual environment. The virtual object corresponded dynamically to the forces and torques applied by the three fingers. The application of the isometric finger device for multi-fingered interaction is demonstrated in four tasks aimed at the rehabilitation of hand function in stroke patients. The tasks include opening the combination lock on a safe, filling and pouring water from a glass, muscle strength training with an elastic torus, and a force tracking task. The training tasks were designed to train patients’ grip force coordination and increase muscle strength through repetitive exercises. The presented virtual reality system was evaluated in a group of healthy subjects and two post-stroke patients (early post-stroke and chronic) to obtain overall performance results. The healthy subjects demonstrated consistent performance with the finger device after the first few trials. The two post-stroke patients completed all four tasks, however, with much lower performance scores as compared to healthy subjects. The results of the preliminary assessment suggest that the patients could further improve their performance through virtual reality training
Human factors in instructional augmented reality for intravehicular spaceflight activities and How gravity influences the setup of interfaces operated by direct object selection
In human spaceflight, advanced user interfaces are becoming an interesting mean to facilitate human-machine interaction, enhancing and guaranteeing the sequences of intravehicular space operations. The efforts made to ease such operations have shown strong interests in novel human-computer interaction like Augmented Reality (AR). The work presented in this thesis is directed towards a user-driven design for AR-assisted space operations, iteratively solving issues arisen from the problem space, which also includes the consideration of the effect of altered gravity on handling such interfaces.Auch in der bemannten Raumfahrt steigt das Interesse an neuartigen Benutzerschnittstellen, um nicht nur die Mensch-Maschine-Interaktion effektiver zu gestalten, sondern auch um einen korrekten Arbeitsablauf sicherzustellen. In der Vergangenheit wurden wiederholt Anstrengungen unternommen, Innenbordarbeiten mit Hilfe von Augmented Reality (AR) zu erleichtern. Diese Arbeit konzentriert sich auf einen nutzerorientierten AR-Ansatz, welcher zum Ziel hat, die Probleme schrittweise in einem iterativen Designprozess zu lösen. Dies erfordert auch die Berücksichtigung veränderter Schwerkraftbedingungen