766 research outputs found

    Conception et évaluation d’un simulateur à réalité virtuelle d’intervention laparoscopique actionné par des embrayages magnétorhéologiques

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    La laparoscopie est une technique chirurgicale qui offre une alternative moins invasive à la chirurgie abdominale traditionnelle, en permettant aux patients de récupérer plus rapidement et avec moins de douleur. Dès son arrivée, cette nouvelle technique a su révolutionner le monde de la chirurgie, mais cette révolution est d'ailleurs venue avec un cout, une formation longue et difficile. Des simulateurs haptiques ont tenté de rendre cet apprentissage plus facile, mais leur cout élevé et leurs grosses dimensions les rendent difficiles d'accès pour les étudiants moyens. Afin de résoudre ce problème, des concepts qui utilisent des dispositifs haptiques sont offerts sur le marché pour concevoir des plateformes de simulation d'interventions laparoscopiques. Ces plateformes sont toutefois peu fidèles à la réalité et n'atteignent pas simultanément les performances dynamiques et cinétiques nécessaires à un apprentissage adéquat. En effet, les moteurs électriques utilisés obligent les concepteurs de dispositifs haptiques à faire un compromis entre la force produite et la réponse dynamique du système. Cette approche pourrait par contre être utilisée avec un dispositif haptique nouvelle-génération, le T-Rex. Ce dernier a été développé récemment par Exonetik, une compagnie issue de recherches de l'Université de Sherbrooke. Contrairement aux dispositifs haptiques offerts sur le marché, le T-Rex utilise la technologie d'actionneurs magnéto-rhéologiques développée par Exonetik. Cette technologie pourrait permettre d'atteindre les performances dynamiques et cinétiques nécessaires à la formation de chirurgiens. Ce projet de recherche présente l'analyse préliminaire du T-Rex d'Exonetik en tant que simulateur à réalité virtuelle d'interventions laparoscopiques. Un simulateur à réalité virtuelle d'interventions laparoscopiques utilisant le T-Rex d'Exonetik en tant qu'interface haptique a été conçu. Des critères de performances ont été établis à l'aide de la littérature pour faire une évaluation quantitative du système. Des simulations utilisant la méthode des éléments finis ont aussi été développées pour faire une évaluation qualitative du système auprès de résidents et de chirurgiens. L'évaluation quantitative du système démontre qu'il répond aux quatre critères cinématiques ainsi qu'à trois des quatre critères cinétiques. Les résultats démontrent donc que l'utilisation d'actionneurs magnéto-rhéologiques dans les simulateurs à réalité virtuelle d'interventions laparoscopiques a beaucoup de potentiel. Par contre, la friction dans le système se doit d'être adressée dans les itérations futures du système

    Development of a Novel Ball-and-Socket Flexible Manipulator for Minimally Invasive Flexible Surgery

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    This work proposes a novel flexible manipulator consisting of a series of 2-DOF vertebrae based on a ball-andsocket joint that is connected by a ball-shaped surface and a cupshaped socket and constrained by pins for circumferential rotation. This manipulator can demonstrate outstanding torsional stiffness since the circumferential rotation between the vertebrae is constrained by four ball pins. The point contact between ball pins and guideways effectively reduces the friction between the vertebrae, thus allowing the designed manipulator to yield a smooth bending shape with constant curvature. This manipulator features high axial and torsional stiffness, excellent bending performance, sufficient loading capacity, and convenient integration with surgical instruments. Moreover, the excellent torsional stiffness enables this manipulator to efficiently transfer torque and be applied in in-situ torsional motion, effectively addressing the typical issue of limited dexterity for torsional motion. The kinematic modeling of the proposed manipulator under in-situ torsional motion has been derived, and its workspace has been analyzed. A robotic system has been assembled, and experiments have verified the proposed design and modeling validity. The results show that the maximum position errors in bending motion are 2.39% (horizontal direction) and 1.98% (vertical direction), and its torsional stiffness is 21.13N∙mm/deg, which is 46 times higher than that of a typical spherical flexible manipulator (SFM). Such merits support this manipulator excellently performing the in-situ torsional motion with a maximum average position error of 3.58%. Furthermore, a phantom test of the larynx has been performed to verify the potential of clinical feasibility

    Collaborative Trolley Transportation System with Autonomous Nonholonomic Robots

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    Cooperative object transportation using multiple robots has been intensively studied in the control and robotics literature, but most approaches are either only applicable to omnidirectional robots or lack a complete navigation and decision-making framework that operates in real time. This paper presents an autonomous nonholonomic multi-robot system and an end-to-end hierarchical autonomy framework for collaborative luggage trolley transportation. This framework finds kinematic-feasible paths, computes online motion plans, and provides feedback that enables the multi-robot system to handle long lines of luggage trolleys and navigate obstacles and pedestrians while dealing with multiple inherently complex and coupled constraints. We demonstrate the designed collaborative trolley transportation system through practical transportation tasks, and the experiment results reveal their effectiveness and reliability in complex and dynamic environments

    Surgical Subtask Automation for Intraluminal Procedures using Deep Reinforcement Learning

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    Intraluminal procedures have opened up a new sub-field of minimally invasive surgery that use flexible instruments to navigate through complex luminal structures of the body, resulting in reduced invasiveness and improved patient benefits. One of the major challenges in this field is the accurate and precise control of the instrument inside the human body. Robotics has emerged as a promising solution to this problem. However, to achieve successful robotic intraluminal interventions, the control of the instrument needs to be automated to a large extent. The thesis first examines the state-of-the-art in intraluminal surgical robotics and identifies the key challenges in this field, which include the need for safe and effective tool manipulation, and the ability to adapt to unexpected changes in the luminal environment. To address these challenges, the thesis proposes several levels of autonomy that enable the robotic system to perform individual subtasks autonomously, while still allowing the surgeon to retain overall control of the procedure. The approach facilitates the development of specialized algorithms such as Deep Reinforcement Learning (DRL) for subtasks like navigation and tissue manipulation to produce robust surgical gestures. Additionally, the thesis proposes a safety framework that provides formal guarantees to prevent risky actions. The presented approaches are evaluated through a series of experiments using simulation and robotic platforms. The experiments demonstrate that subtask automation can improve the accuracy and efficiency of tool positioning and tissue manipulation, while also reducing the cognitive load on the surgeon. The results of this research have the potential to improve the reliability and safety of intraluminal surgical interventions, ultimately leading to better outcomes for patients and surgeons

    Viral Bodies: AIDS and Other Contagions in Latin American Life Narratives

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    The HIV/AIDS crisis in Latin America was overshadowed by the late phase of the Cold War, while authoritarian governments promoted discourses reflecting moral and ethical exceptionalism. People with AIDS (PWAs) experienced multiple crises—moral excision by the state, marginalization, and the certainty of death. Existing societal infrastructures of class, race, ethnicity, gender, and sexuality urged their marginalized lives into even more precarious ways of being. The authoritarian and hegemonic discourses complicated and intensified how PWAs experienced isolation, internal exile, neglect, condemnation, discrimination, and death. These exceptional conditions led to a 10-year delay before works by Latin American artists and writers emerged. My dissertation examines works by Reinaldo Arenas (Cuba), Pedro Lemebel (Chile), and Pablo Perez (Argentina) since they reveal a spectrum of intersectional AIDS subjectivities exhibiting accommodation, resistance, and transgression of prevailing national and religious norms. Drawing from the fields of exile studies, transfeminism, contagion theory, and virality, my dissertation argues that these narratives break imposed silences by radically exteriorizing the insularity, anonymity, and decomposing bodies of those dying, and living, with the disease. They intervene in national, transnational, and religious discourses. They also challenge the limits of gender and genre, while contributing to a (re)imagining of homosexual history. They offer utopian visions of kinship, belonging, and community formation and bring practices of difference such as transvestism, sadomasochism, and spiritual fetishism into focus

    Intuitive Telemanipulation of Hyper-Redundant Snake Robots within Locomotion and Reorientation using Task-Priority Inverse Kinematics

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    Snake robots offer considerable potential for endoscopic interventions due to their ability to follow curvilinear paths. Telemanipulation is an open problem due to hyper-redundancy, as input devices only allow a specification of six degrees of freedom. Our work addresses this by presenting a unified telemanipulation strategy which enables follow-the-leader locomotion and reorientation keeping the shape change as small as possible. The basis for this is a novel shape-fitting approach for solving the inverse kinematics in only a few milliseconds. Shape fitting is performed by maximizing the similarity of two curves using Fréchet distance while simultaneously specifying the position and orientation of the end effector. Telemanipulation performance is investigated in a study in which 14 participants controlled a simulated snake robot to locomote into the target area. In a final validation, pivot reorientation within the target area is addressed.© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

    2009 GREAT Day Program

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    SUNY Geneseo’s Third Annual GREAT Day.https://knightscholar.geneseo.edu/program-2007/1003/thumbnail.jp
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