41 research outputs found

    Kinesthetic Cues that Lead the Way

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    On the development of a cybernetic prosthetic hand

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    The human hand is the end organ of the upper limb, which in humans serves the important function of prehension, as well as being an important organ for sensation and communication. It is a marvellous example of how a complex mechanism can be implemented, capable of realizing very complex and useful tasks using a very effective combination of mechanisms, sensing, actuation and control functions. In this thesis, the road towards the realization of a cybernetic hand has been presented. After a detailed analysis of the model, the human hand, a deep review of the state of the art of artificial hands has been carried out. In particular, the performance of prosthetic hands used in clinical practice has been compared with the research prototypes, both for prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by comparing the characteristics of these hands with the natural model, the human hand, the limitations of current artificial devices will be put in evidence, thus outlining the design goals for a new cybernetic device. Three hand prototypes with a high number of degrees of freedom have been realized and tested: the first one uses microactuators embedded inside the structure of the fingers, and the second and third prototypes exploit the concept of microactuation in order to increase the dexterity of the hand while maintaining the simplicity for the control. In particular, a framework for the definition and realization of the closed-loop electromyographic control of these devices has been presented and implemented. The results were quite promising, putting in evidence that, in the future, there could be two different approaches for the realization of artificial devices. On one side there could be the EMG-controlled hands, with compliant fingers but only one active degree of freedom. On the other side, more performing artificial hands could be directly interfaced with the peripheral nervous system, thus establishing a bi-directional communication with the human brain

    Standing Device for a Six Year Old Student

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    A six-year-old student with cerebral palsy is unable to stand on her own due to her condition which inhibits control of motor skills and hinders muscular development. While several commercial standing devices currently exist, these devices do not accommodate for knee flexion and therefore are ineffective for this student. The goal of this project was to design and manufacture an easily operable standing device tailored to her specific needs and school environment. The device will accommodate her growth over the next five years and allows for a wide range of adjustability of both angle inclination of the user’s body as well as the angle support of knee flexion. Initial field tests were successful and the device was met with great satisfaction from the client and her physical therapist

    Enactive Sound Machines: Theatrical Strategies for Sonic Interaction Design

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    Embodied interaction with digital sound has been subject to much prior research, but a method of coupling simple and intuitive hand actions to the vast potential of digital soundmaking in a perceptually meaningful way remains elusive. At the same time, artistic practices centred on performative soundmaking with objects remain overlooked by researchers. This thesis explores the design and performance of theatre sound effects in Europe and the U.S. in the late nineteenth and early twentieth century in order to converge the embodied knowledge of soundmaking at the heart of this historical practice with present-day design and evaluation strategies from Sonic Interaction Design and Digital Musical Instrument design. An acoustic theatre wind machine is remade and explored as an interactive sounding object facilitating a continuous sonic interaction with a wind-like sound. Its main soundmaking components are digitally modelled in Max/MSP. A prototype digital wind machine is created by fitting the acoustic wind machine with a rotary encoder to activate the digital wind-like sound in performance. Both wind machines are then evaluated in an experiment with participants. The results show that the timbral qualities of the wind-like sounds are the most important factor in how they are rated for similarity, that the rotational speed of both wind machines is not clearly perceivable from their sounds, and that the enactive properties of the acoustic wind machine have not yet been fully captured in the digital prototype. The wind machine’s flywheel mechanism is also found to be influential in guiding participants in their performances. The findings confirm the acoustic wind machine’s ability to facilitate enactive learning, and a more complete picture of its soundmaking components emerges. The work presented in this thesis opens up the potential of mechanisms to couple simple hand actions to complex soundmaking, whether acoustic or digital, in an intuitive way

    The Hand-Held Force Magnifier: Surgical Tools to Augment the Sense of Touch

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    Modern surgeons routinely perform procedures with noisy, sub-threshold, or obscured visual and haptic feedback,either due to the necessary approach, or because the systems on which they are operating are exceeding delicate. For example, in cataract extraction, ophthalmic surgeons must peel away thin membranes in order to access and replace the lens of the eye. Elsewhere, dissection is now commonly performed with energy-delivering tools – rather than sharp blades – and damage to deep structures is possible if tissue contact is not well controlled. Surgeons compensate for their lack of tactile sensibility by relying solely on visual feedback, observing tissue deformation and other visual cues through surgical microscopes or cameras. Using visual information alone can make a procedure more difficult, because cognitive mediation is required to convert visual feedback into motor action. We call this the “haptic problem” in surgery because the human sensorimotor loop is deprived of critical tactile afferent information, increasing the chance for intraoperative injury and requiring extensive training before clinicians reach independent proficiency. Tools that enhance the surgeon’s direct perception of tool-tissue forces can therefore potentially reduce the risk of iatrogenic complications and improve patient outcomes. Towards this end, we have developed and characterized a new robotic surgical tool, the Hand-Held Force Magnifier (HHFM), which amplifies forces at the tool tip so they may be readily perceived by the user, a paradigm we call “in-situ” force feedback. In this dissertation, we describe the development of successive generations of HHFM prototypes, and the evaluation of a proposed human-in-the-loop control framework using the methods of psychophysics. Using these techniques, we have verified that our tool can reduce sensory perception thresholds, augmenting the user’s abilities beyond what is normally possible. Further, we have created models of human motor control in surgically relevant tasks such as membrane puncture, which have shown to be sensitive to push-pull direction and handedness effects. Force augmentation has also demonstrated improvements to force control in isometric force generation tasks. Finally, in support of future psychophysics work, we have developed an inexpensive, high-bandwidth, single axis haptic renderer using a commercial audio speaker

    The development of stage machinery in the nineteenth century British theatre : a study of physical and documentary evidence

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    Thc devolopment of scene changing machinery in Great Britain is perhaps one of the few disciplines in the field of mechanical engineering which have virtually never relied upon new discoveries in technology for their advancement. Instead it has always lagged behind, perhaps modifying, certainly adapting, existing techniques. This study aims to examine the evolution of stage machinery during the nineteenth century, when many techniques had already been in existence and traditions firmly established since the previous century. The degree of development in the course of the nineteenth century was in many ways a reflection of the type of drama presented. As time went by, the public's taste for spectacle and visual presentation intensified and fostered an increase in the complexity of scene changing equipment. This in turn meant that many of the theatres built in the eighteenth century, especially in the provinces, were sadly inadequate for housing the vast quantities of equipment which machinists needed to install above and below the stage. As a result architects, began improving and enlarging existing theatres as well as building new ones, with increased stage width and depth, increased flying space above and increased depth below the stage.There was indeed an enormous rise in demand for scenic effects shortly after the beginning of the nineteenth century. This rapid growth caused the smaller existing Georgian playhouses, like the Theatre Royal, Ipswich, either to be modified in an attempt to cater for new trends, or to close. This dilemma alone must be acknowledged as a significant contributory factor in the decline of the Georgian playhouse and helps to explain the comparatively small number of such theatres surviving to the present day.The techniques of the stage machinist in the first half of the nineteenth century relied almost totally on  technology and basic engineering principles which had existed for many years. Certainly the comparison often made between the backstage of a theatre of this period and a sailing ship is a very apt one, since both relied on manually hauled ropes, sheaves and the principles of mechanical advantage. However, these techniques had also been utilised for other, non-theatrical purposes. For instance, housed in the central tower of Beverley Minster is a large treadwheel, which was, and is still, used to raise equipment from ground level into the roof space [sec photo.1]. This is based upon the principles of mechanical advantage, in much the same way as many pieces of scene-changing equipment.Thus, because the theatrical profession was slow to adopt now apparatus and constantly replacing old machinery with brand new near-replicas, its evolution was comparatively slow. The job of a stage machinist was quite often a family concern, as the techniques, traditions, secrets and tricks of the trade were passed from father to son. The Sloman family and the Grieve family were particularly well known in London for their knowledge and expertise in this hold. Change was to a greater or lessor extent resisted and in any case many saw little need for change, especially those who were steeped in the traditions of the machinist and his machinery. It was, in fact, this basic resistance which caused a disruption in the evolutionary development of stage machinery. Many theatre architects were happy to furnish a traditional stage machinist with a blank drawing denoting "The Stage", requiring him to fill in the details as he saw fit, whilst the innovators devised all manner of new equipment, that which worked and sometimes that which emphatically did not. There was therefore a bifurcation, with the 'traditional school' refining the 'English wood stage' to a higher degree of sophistication, whilst the 'modern school' developed and attempted to apply the engineering technology associated with other disciplines. In essence, the latter attempted to replace muscle power with hydraulic or electrical power.This thesis documents the development of stage machinery from its comparatively primitive state at the beginning of the nineteenth century, through years of growth and expansion, and finally into the last decade of the century, when theatrical productions were in truth exercises in spectacle

    Haptics: Science, Technology, Applications

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    This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications

    Analysis of the backpack loading efects on the human gait

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    Gait is a simple activity of daily life and one of the main abilities of the human being. Often during leisure, labour and sports activities, loads are carried over (e.g. backpack) during gait. These circumstantial loads can generate instability and increase biomechanicalstress over the human tissues and systems, especially on the locomotor, balance and postural regulation systems. According to Wearing (2006), subjects that carry a transitory or intermittent load will be able to find relatively efficient solutions to compensate its effects.info:eu-repo/semantics/publishedVersio

    NASA Tech Briefs, Summer 1984

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    Topics include: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology. New Product Ideas: A summary of selected innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Science
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