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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.
181

Haptic emulation of hard surfaces with applications to orthopaedic surgery

Hungr, Nikolai Anthony 05 1900 (has links)
A generally accepted goal in orthopaedic surgery today is to maximize conservation of tissue and reduce tissue damage. Bone-conserving implants have bone-mating surfaces that reproduce the natural curvature of bone structures, requiring less bone removal. No small, reliable, inexpensive and universal bone sculpting technique currently exists, however, that can both create and accurately align such complex surfaces. The goal of this thesis was to develop a haptic hard surface emulation mechanism that could be applied to curvilinear bone sculpting using a surgical robot. A novel dynamic physical constraint concept was developed that is able to emulate realistic hard constraints, smooth surface following, and realistic surface rigidity, while allowing complete freedom of motion away from the constraints. The concept was verified through the construction of a two-link manipulator prototype. Tests were run on nine users that involved each user tracing out five different virtual surfaces on a drawing surface using the prototype. The primary purposes of prototype testing were to obtain subjective data on how effectively the dynamic physical constraint concept simulates simple surfaces, to assess how it reacts to typical user interactions and to identify any unexpected behaviour. Users were 100% satisfied with the prototype’s ability to emulate realistic and stiff hard surfaces and with its ease of manipulation. The amount of incursion into each of the virtual surfaces by all the users was measured to assess the precision of the system with the goal of deciding whether this new haptic concept should be further developed specifically for precision applications such as surgery. For curvilinear surfaces, 90% of the cumulative distribution of the measured data was less than 2mm, while for linear surfaces it was less than 6mm. Four behavioural effects were noticed: lateral deflection, reverse ‘stickiness’, hysteresis and instability in certain areas. These effects were studied in detail to determine how to either eliminate them or to minimize them through system design optimization. A computer simulation was also used to model the behaviour of the prototype and to gain further understanding of these effects. These analyses showed that the concept can be successfully used in curvilinear bone sculpting.
182

Pulse, pulse, somersault

Gorodi, Suzie Mei January 2009 (has links)
This project explores notions of seeing and knowing, underpinned by performative and phenomenological fields of enquiry that relate this exploration to the sensate experience of the viewer. A specific interest considers ideas of embodied vision with an aim at generating events that vacillate in the bodies of the audience. A primary focus is on the arena of encounter as a multi-sensory experiential event, and within this context this project proposes a temporal and spatial framework for exploration. Studio methods develop a cinematic-body of video work negotiating performative practice involving video projection and temporality. Pivotal goals are to explore the significance of the ‘chiasm’ between seeing and knowing, raising questions about how humans see, and how humans make how they see matter. Therefore, this thesis project progresses along experimental approaches to video installation, particularly in relation to the phenomena of encounter, the viewer, and film experience. The central motivation of this video practice is aimed at corporeal affect in the body/s of the audience. This thesis project is constituted as 80% practice-based work accompanied by a 20% exegesis.
183

Mechanical linkage design for haptic rehabilitation and development of fine motor skills /

Streng, Bradley Taylor. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 68-71). Also available on the World Wide Web.
184

Admittance and impedance haptic control for realization of digital clay as an effective human machine interface (HMI) device

Ngoo, Cheng Shu. January 2009 (has links)
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Book, Wayne; Committee Member: Glezer, Ari; Committee Member: Sadegh, Nader. Part of the SMARTech Electronic Thesis and Dissertation Collection.
185

'I've got a feeling' : the effect of haptic information on the preferred location of purchase of guitars and stringed wooden instruments

Pirie, Elliot January 2017 (has links)
This thesis develops technology adoption and sensory information literatures through an evaluation of antecedents to consumers’ purchase location intention of Musical Instruments (MI). With the unique factor of instrument heterogeneity MI e-retail sales are information asymmetric propositions, where the consumer may make a sub-optimal purchase online having foregone the opportunity to experience the haptic information required to ascertain the instrument’s true quality. Despite a reticent adoption of MI e-retail from the traditional retail industry online MI sales are increasing, resulting in off-line marketplace contraction, thus investigation of consumers’ online MI purchase motivations is of value to the industry. The exploration of this topic uses a pragmatic, two-stage mixed-methods process incorporating inductive in-depth interviews with MI retail industry personnel, followed by deductive MI consumer based quantitative questionnaires. The reluctance to adopt e-retail is based on ‘expertise-led aversion’ and ‘expertise gap’ where key MI retail influencers attempt to enforce their own views on the correct way to purchase an instrument, rather than responding to consumer trends. This aversion was influenced by their own reliance on haptic information, coupled with knowledge of instrument heterogeneity and their level of musicianship. Consumer research conclusions identify that high haptic-need consumers, who tend to have greater ability and involvement, are more likely to purchase in-store whilst those with lower haptic needs are more willing to purchase MI online. Through the design and empirical testing of the Musical Instrument Need-for-Touch (MINFT) model numerous factors were identified as moderators to this basic supposition. The subsequent development of a MI consumer typology identified five distinct groups that respond to differing stimuli in relation to MI purchase location intention. These findings add to the academic discourse and enable MI retailers to enhance their offerings both in-store and online, leading to more effective targeting of their key customers.
186

Conception, fabrication et caractérisation d'une dalle haptique à base de micro-actionneurs piézoélectriques / Conception, fabrication and characterization of an haptic plate based on piezoelectric micro-actuators

Bernard, François 10 June 2016 (has links)
Les systèmes haptiques, ou systèmes de simulation de textures, sont aujourd'hui en plein essor et représentent le prochain challenge pour les appareils mobiles. L'une des solutions les plus prometteuses est celle à base de réduction de friction par vibrations ultrasoniques. L'objectif de cette thèse est de développer une solution haptique répondant au critère d’intégration de la téléphonie mobile en termes d’intégration et de consommation électrique. Plus précisément, il est de proposer une solution à base de couches minces piézoélectriques déposées sur une plaque transparente de la taille d’un écran de smartphone. Après avoir identifié les phénomènes de perception tactile, nous avons établi les spécifications du cahier des charges permettant obtenir un stimulateur haptique. Un modèle théorique de vibration, basé sur la réflexion des ondes de Lamb, nous a permis de déterminer les modes de vibration répondant à ce cahier des charges pour une plaque de la taille d’un smartphone d'écran 5 pouces libre de toutes contraintes. Des transducteurs piézoélectriques en nitrure d’aluminium sont utilisés pour la mise en vibration du système haptique. Déposés sur une face de la plaque, leur position et leur dimensionnement ont été optimisés grâce à des simulations par éléments finis. Le dispositif tactile final sera conçu de façon à laisser un espace central transparent de 4 pouces de diagonal permettant l’ajout d’un écran LCD. Le prototype ainsi déterminé, il est fabriqué grâce à des techniques de dépôt et de gravure en salle blanche. Le dispositif réalisé est caractérisé électriquement et mécaniquement. On détermine alors la puissance nécessaire pour la mise en vibration de la plaque avec des amplitudes correspondant au cahier des charges. Une optimisation de l’électronique de commande permet de réduire la puissance d’actionnement de ce système. Des transducteurs, utilisés en capteurs, sont caractérisés. Ces derniers seront utilisés pour asservir le système dans le cas d’un appui simulant le doigt sur la plaque. / Haptic rendering systems, or textural recreated systems, are nowaday in constant expension and represent the next challenge for the mobile devices. One of the promising solution is based on the friction reduction generated by ultrasonic waves. The aim of this PhD is to develop an haptic rendering solution taking into account the issues of integration into mobile devices in terms of power consumption. More precisely, a solution based on piezoelectric thin films deposited onto a smartphone-sized transparent plate is proposed. Understanding the tactile perception phenomenons, the physical specifications are established in order to obtain an haptic stimulator. A theoretical model based on the Lamb wave reflections determined the vibration modes corresponding to the specifications for a constrain-free 5-inch smartphone size plate.The plate is put into vibration by Aluminum Nitrite thin-film piezoelectric transducers. Processed on one side of the plate, their dimension and position have been optimized thanks to finite element simulations. The final tactile prototype is designed allowing a 4-inch clear centrale space for positioning a futur LCD screen. After this design, the prototype is fabricated with cleanroom processes. The device is then electrically and mechanically characterized. The minimum power necessary to put in vibration the plate is determined, with the minimum specified vibration amplitude. The electronic for the actuation is optimized in order to reduce the power consumption of the system. Transducers, used as sensors, are characterized in order to create a feedback loop. A user case is finally studied to compensate the influence of the finger.
187

A Haptic Simulator for Gastrointestinal Endoscopy : Design Development and Experiments

Chakravarthy, Shanthanu January 2015 (has links) (PDF)
Endoscopy is an involved clinical practice requiring considerable skill in performing the procedure. Virtual reality together with haptics offers immersive, flexible, and cost-effective platform for training in endoscopic procedures. In this thesis, we present mechanical design, control, characterization, and integration of a novel endoscopic haptic simulator with three degrees of freedom. Related ideas, computations, and experiments that support endoscopy and endoscopic simulator are also investigated in this thesis. The haptic device is designed to reflect forces in the three important directions, namely, longitudinal, rotational, and radial directions. The mechanical design of the haptic device overcomes some of the limitations of the existing systems. The device provides large sustained output force and possesses low friction, low inertia and zero backlash. Dynamics-based feed-forward control algorithm is developed to achieve high fidelity and transparency in force-feedback. Tracking performance, transparency, and nonlinearity are all quantified using experiments designed to validate the control structure and to characterize the developed haptic device. The device is shown to apply a maximum continuous force of 11 N in the longitudinal direction, maximum continuous torque of 196 mN.m in the rotational DoF, and a maximum force of 1.5 N (at each of the four radial pads) in the radial direction. Furthermore, we also present the design of a novel compliant mechanism for the radial DoF. The circumferentially actuated compliant (CAC) mechanism is a planar, reversible, and single degree-of-freedom compliant mechanism that emulates controlled and responsive circularly shaped opening. The mechanism is designed in view of the anatomy of the throat and the special manoeuvre required for intubation of the endoscope into the oesophagus by avoiding the trachea. As part of the auxiliary work for the endoscopic simulator, we developed a computational technique for simulating the shape of the entire endoscope during endoscopy. Strain measurements made at discrete locations along the length of endoscope are used in the method. Strain measurement, stain interpolation, and shape reconstruction based on strain information are discussed. Furthermore, a method to predict the location of point forces acting on the endoscope tube during endoscopy is proposed. A novel concept of haptic playback for endoscopy is also investigated in this work. Haptic playback aids the endoscopists to recall both visual as well as haptic information from an earlier endoscopic session. The endoscopic playback concept is evaluated using psychophysical experiments. Through these experiments, we quantified haptic perception through the endoscope, the effect of temporal separation on haptic memory, and the interaction between haptic and visual information in sensory processing.
188

A levels-of-precision approach for physics-based soft tissues modeling / Uma abordagem de níveis de precisão para modelagem de tecidos moles fisicamente baseados

Silva, Daniele Fernandes e January 2015 (has links)
Simulação computacional de ambientes cirúrgicos têm sido amplamente utilizados, normalmente para treinamentos, ajudando no desenvolvimento de habilidades essenciais e minimizando erros em procedimentos cirúrgicos. Para estes ambientes, é essencial a obtenção de um comportamento mais realista, sendo importante o uso de técnicas com alta precisão, além de uma simulação em tempo real. A fim de melhor controlar este trade-off entre eficiência e eficácia, apresentamos um ambiente híbrido e adaptativo que combina um conjunto de métodos para alcançar uma boa precisão e desempenho na simulação. Nosso sistema mescla métodos físicos de deformação (Método de Elementos Finitos e Mass-Mola) com um método não-físico que aproxima o comportamento dos primeiros (Green Coordinates), sendo capaz de utilizar o método apropriado dependendo da situação. Para melhor simular um ambiente cirúrgico completo, foram implementadas ferramentas adicionais para interação, permitindo pegar e manipular, queimar, e sentir os objetos do cenário. Nosso sistema proporciona grande imersão ao usuário, consumindo menos recursos computacionais e aumentando as taxas de atualização da simulação. / Computational simulation of surgical environments have been widely used usually for trainings, improving essential skills and minimizing errors in surgical procedures. As these environments are always looking for a more realistic behavior, it is important to use high-precision techniques while ensuring a real-time simulation. In order to better manage this trade-off between efficiency and effectiveness, we present a hybrid and adaptive environment that combines a set of methods to achieve good accuracy and performance for a simulation. Our system merges physically deformation methods (Finite Elements Method and Mass Spring Damper) with a non-physical method that approximates the formers behavior (Green Coordinates), being able to use the appropriate method depending on the situation. To simulate an approximation of a complete surgical environment, we also implement interaction tools, such as picking, burning, and haptic feedback. Our system provides great immersion for the user, consuming less computational resources and increasing update rates.
189

Designing tactile vocabularies for human-computer interaction / Projetando vocabulários táteis para interação humano-computador

Oliveira, Victor Adriel de Jesus January 2014 (has links)
Esta dissertação apresenta um estudo sobre linguagens táteis em interação humanocomputador e uma nova abordagem de prefixação vibrotátil. Nós pretendemos analisar como as escolhas feitas durante o processo de concepção de vocabulários táteis afetam o desempenho do usuário em uma tarefa interativa. Por isso desenvolvemos e testamos diferentes conjuntos de sinais táteis para suporte à navegação em ambientes virtuais. Isso nos levou a esboçar o conceito de Padrão Tátil Modificador para comunicação vibrotátil que foi testado por meio de experimentos com usuários. Na avaliação dos vocabulários táteis construídos com padrões modificadores foram considerados os efeitos de estimulação multisensorial, fatores relacionados ao processamento de seqüências táteis e o mascaramento causado pela exibição de múltiplos estímulos ao mesmo tempo. Resultados mostram que os participantes que usaram vocabulários construídos com padrões modificadores obtiveram desempenho melhor na tarefa de navegação. Esse e outros resultados relacionados à percepção, aprendizagem e interpretação dos nossos vocabulários atestam a validade do uso de modificadores na construção de linguagens táteis. As conclusões extraídas deste trabalho se mostram úteis no auxílio à concepção de interfaces táteis que sejam usáveis e que demandem expressividade de seus vocabulários. / This thesis presents a study about tactile languages in human-computer interaction and a novel approach for vibrotactile prefixation. We intended to analyse how the choices made during the design process of tactile vocabularies would affect the user performance on an interactive task. Therefore, we have designed and tested different sets of tactile signals for aid navigation in virtual environments. It leaded us to fashion the concept of Modifier Tactile Pattern for vibrotactile communication which was tested through user experiments. In the assessment of the modifier-based vocabularies we attempted to effects of multisensory stimulation, factors related to the processing of tactile sequences and masking caused by multiple stimuli delivered in a same time. Results show that those participants who used modifier-based vocabularies performed better the navigation task. That and others results related to perception, learning and interpretation of our tactile vocabularies show the validity of the use of modifiers on tactile languages. The statements made from this work will be useful for designing usable tactile interfaces that demand expressive vocabularies.
190

A Maker's Mechanological Paradigm: Seeing Experiential Media Systems as Structurally Determined

January 2015 (has links)
abstract: Wittgenstein’s claim: anytime something is seen, it is necessarily seen as something, forms the philosophical foundation of this research. I synthesize theories and philosophies from Simondon, Maturana, Varela, Wittgenstein, Pye, Sennett, and Reddy in a research process I identify as a paradigm construction project. My personal studio practice of inventing experiential media systems is a key part of this research and illustrates, with practical examples, my philosophical arguments from a range of points of observation. I see media systems as technical objects, and see technical objects as structurally determined systems, in which the structure of the system determines its organization. I identify making, the process of determining structure, as a form of structural coupling and see structural coupling as a means of knowing material. I introduce my theory of conceptual plurifunctionality as an extension to Simondon’s theory. Aspects of materiality are presented as a means of seeing material and immaterial systems, including cultural systems. I seek to answer the questions: How is structure seen as determining the organization of systems, and making seen as a process in which the resulting structures of technical objects and the maker are co-determined? How might an understanding of structure and organization be applied to the invention of contemporary experiential media systems? / Dissertation/Thesis / Doctoral Dissertation Media Arts and Sciences 2015

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