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Development of a Force Sensor Mechanism for the Bare Fiber Polishing MachineChang, Chung-heng 17 February 2005 (has links)
Because the need of high speed data transmission is increasing day by day, fiber optic communication have played an important role. However, with increasing of the data transmission distance, the loss of the power is a series problem. To solve this problem, the power of the signal must be amplified in a fixed distance to keep the signal reality. In the optic amplified system, the pump laser is always a 980nm high-power laser. Because of the high aspect ratio of this laser, the quadrangular- pyramid-shaped fiber endface(QPSFE) lensed fiber is needed in order to increase the coupling efficiency.
There is no standard process to fabricate QPSFE now. The experiment method is as follow. The first procedure is to polish the flat-end fiber to become the QPSFE, then melt the fiber by electric arc, the QPSFE lensed fiber is formed finally. In the polishing step, the bare fiber polishing machine is used. But, the polished quantity is unavailable during polishing, so the yield of the well-polished fibers is poor, only 20%. In this research, the force sensing mechanism mounted in the polishing machine is proposed to measure the force between the fiber and the polish disk. By mounting the mechanism, there are several advantages, such as operating conveniently, increasing the polishing speed, and making the polished quantity available during polishing. Using this force sensing mechanism to develop a polish rule will improve the yield of the well-polished fibers.
The strain gauge method is used to design the force sensing mechanism. Using this mechanism and taking the force analysis of the fiber polishing will make the force information between the fiber and the polish disk available. By design the parameters of this mechanism advisably, it will reach the expected purpose in this research. A 0.5
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DIFFERENTIAL DRIVE ROBOTPLATFORM WITH EXTERNALFORCE SENSING CAPABILITIES INTENDED FOR LOGISTICAL TASKS SET IN A HOSPITAL ENVIRONMENTAndersson, Tim, Kihlberg, August January 2020 (has links)
In this thesis, a suitable mechanical design of a di erential drive robot equipped with a force sensingturntable is presented for a logistical robot application in a hospital environment. The focus of thisthesis will be on the mechanical design of the robot, the force sensor, electronics for the force sensorand the development of a dynamic model. The dynamic model takes advantage of the payloadinformation from the force sensor in order to manoeuvre the robot optimally without it falling over.A complete method of measuring and locating a load on top of the table is successfully tested. Asimulation of the robot using the dynamic model and information about external forces from theforce sensor is created, applied and veri ed towards a set of tests with expected reactions fromthe model. The robot platform was built mechanically but not fully assembled with electronics,power sources, etc. The simulations and tests performed upon the robot platform indicates that itful ls the requirements set up in this paper. The dynamic model has not been tested on a physicalplatform but it behaves exactly like expected in the simulations hence tuning is the only expectedobstruction before it can be applied to the real-life platform. The force sensor works as intendedand can accurately measure payload mass by 0:2kg and lever lengths by 0:1m to the payload.The accuracy of the angle approximation relies on the magnitude of the radial torque signal, hencea threshold of the acceptable radial torque magnitude must be determined in order to in turnde ne the worst acceptable radial angle accuracy.
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Multiple Fibre Bragg Grating Force SensorFritzén, Felix January 2023 (has links)
The purpose of this project is to explore the FBG (Fiber Bragg Grating) technology and create a force sensor. The result can be used as a basis for further projects.The project starts with force and strain measurements. The project then evolves to incorporate multiple FBG sensors. An uncommon method of writing the FBG withcoating is tested, which results in a FBG with most of the coating left.The result is a multi-FBG sensor. And even though the individual FBG is not linear the sum shows fantastic linearity with R-square of 0.99999. The change in wavelength is 1328pm/N. A common issue in the strain measurement is discussed and proof is provided. This shows that the reference value of the FBG is 1.12pm/μstrain instead of 1.21pm/μstrain. This is important if the FBG is mounted in a structure, because then the material proprieties will be dominating. Another result is that the peaks of Fabry Perot grating pair are linear but with different coecients.
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Contributions à la commande de bras manipulateurs de robot sous-marin pour la manipulation à grande profondeur d'échantillons biologiques déformables / Contributions to the Coordinated Control of Two Robotic Arms for Underwater Manipulation of Deformable Biological SpecimensLeborne, François 16 November 2018 (has links)
Dans le cadre de la collecte sous-marine d'échantillons biologiques et minéraux pour la recherche scientifique par un robot sous-marin équipé de bras manipulateurs, ce projet de thèse a pour but principal le développement de nouvelles techniques de manipulation des échantillons, plus fiables, permettant d'en assurer l'intégrité physique et leur exploitabilité par les chercheurs. Les nouvelles techniques de manipulation proposées prennent en compte l'actionnement particulier des nouveaux bras électriques sous-marins équipant les engins récents, afin d'augmenter la précision du positionnement des outils embarqués par le manipulateur. Un outil amovible, compliant, et mesurant les efforts d'interaction entre les bras du sous-marin et leur environnement est aussi proposé, et des méthodes permettant de tirer partie des caractéristiques de cet outil sont développées et testées expérimentalement. L'engin sous-marin hybride HROV Ariane, équipé de deux bras électriques hétérogènes, offre la plateforme opérationnelle pour la validation expérimentale des solutions proposées. / The research carried out in the scope of this doctorate degree aims to develop innovative techniques to improve the collection of biological and mineral samples underwater using robotic manipulators. The end goal is to enhance the handling by robotic means in order to maximise sample quality provided to marine scientists. The proposed techniques are based on an in-depth analysis of the robotic arm actuators used in most recent underwater intervention vehicles, in order to improve the accuracy of the positionning of the tools held by the manipulator arms. An instrumented tool has also been developed with the aim to measure the reaction forces and adapt the interaction between the arm's end-effector and its environment to improve samples handling. These methods and the other contributions described in this thesis have been experimentally validated using Ifremer's hybrid-ROV Ariane equipped with two electrically actuated heterogeneous robotic arms.
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Contact force sensing from motion tracking / Capture de forces de contact par capture de mouvementPham, Tu-Hoa 09 December 2016 (has links)
Le sens du toucher joue un rôle fondamental dans la façon dont nous percevons notre environnement, nous déplaçons, et interagissons délibérément avec d'autres objets ou êtres vivants. Ainsi, les forces de contact informent à la fois sur l'action réalisée et sa motivation. Néanmoins, l'utilisation de capteurs de force traditionnels est coûteuse, lourde, et intrusive. Dans cette thèse, nous examinons la perception haptique par la capture de mouvement. Ce problème est difficile du fait qu'un mouvement donné peut généralement être causé par une infinité de distributions de forces possibles, en multi-contact. Dans ce type de situations, l'optimisation sous contraintes physiques seule ne permet que de calculer des distributions de forces plausibles, plutôt que fidèles à celles appliquées en réalité. D'un autre côté, les méthodes d'apprentissage de type `boîte noire' pour la modélisation de structures cinématiquement et dynamiquement complexes sont sujettes à des limitations en termes de capacité de généralisation. Nous proposons une formulation du problème de la distribution de forces exploitant ces deux approches ensemble plutôt que séparément. Nous capturons ainsi la variabilité dans la façon dont on contrôle instinctivement les forces de contact tout en nous assurant de leur compatibilité avec le mouvement observé. Nous présentons notre approche à la fois pour la manipulation et les interactions corps complet avec l'environnement. Nous validons systématiquement nos résultats avec des mesures de référence et fournissons des données exhausives pour encourager et évaluer les travaux futurs sur ce nouveau sujet. / The human sense of touch is of fundamental importance in the way we perceive our environment, move ourselves, and purposefully interact with other objects or beings. Thus, contact forces are informative on both the realized task and the underlying intent. However, monitoring them with force transducers is a costly, cumbersome and intrusive process. In this thesis, we investigate the capture of haptic information from motion tracking. This is a challenging problem, as a given motion can generally be caused by an infinity of possible force distributions in multi-contact. In such scenarios, physics-based optimization alone may only capture force distributions that are physically compatible with a given motion, rather than those really applied. In contrast, machine learning techniques for the black-box modelling of kinematically and dynamically complex structures are often prone to generalization issues. We propose a formulation of the force distribution problem utilizing both approaches jointly rather than separately. We thus capture the variability in the way humans instinctively regulate contact forces while also ensuring their compatibility with the observed motion. We present our approach on both manipulation and whole-body interaction with the environment. We consistently back our findings with ground-truth measurements and provide extensive datasets to encourage and serve as benchmarks for future research on this new topic.
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Teleoperation of MRI-Compatible Robots with Hybrid Actuation and Haptic FeedbackShang, Weijian 28 January 2015 (has links)
Image guided surgery (IGS), which has been developing fast recently, benefits significantly from the superior accuracy of robots and magnetic resonance imaging (MRI) which is a great soft tissue imaging modality. Teleoperation is especially desired in the MRI because of the highly constrained space inside the closed-bore MRI and the lack of haptic feedback with the fully autonomous robotic systems. It also very well maintains the human in the loop that significantly enhances safety. This dissertation describes the development of teleoperation approaches and implementation on an example system for MRI with details of different key components. The dissertation firstly describes the general teleoperation architecture with modular software and hardware components. The MRI-compatible robot controller, driving technology as well as the robot navigation and control software are introduced. As a crucial step to determine the robot location inside the MRI, two methods of registration and tracking are discussed. The first method utilizes the existing Z shaped fiducial frame design but with a newly developed multi-image registration method which has higher accuracy with a smaller fiducial frame. The second method is a new fiducial design with a cylindrical shaped frame which is especially suitable for registration and tracking for needles. Alongside, a single-image based algorithm is developed to not only reach higher accuracy but also run faster. In addition, performance enhanced fiducial frame is also studied by integrating self-resonant coils. A surgical master-slave teleoperation system for the application of percutaneous interventional procedures under continuous MRI guidance is presented. The slave robot is a piezoelectric-actuated needle insertion robot with fiber optic force sensor integrated. The master robot is a pneumatic-driven haptic device which not only controls the position of the slave robot, but also renders the force associated with needle placement interventions to the surgeon. Both of master and slave robots mechanical design, kinematics, force sensing and feedback technologies are discussed. Force and position tracking results of the master-slave robot are demonstrated to validate the tracking performance of the integrated system. MRI compatibility is evaluated extensively. Teleoperated needle steering is also demonstrated under live MR imaging. A control system of a clinical grade MRI-compatible parallel 4-DOF surgical manipulator for minimally invasive in-bore prostate percutaneous interventions through the patient’s perineum is discussed in the end. The proposed manipulator takes advantage of four sliders actuated by piezoelectric motors and incremental rotary encoders, which are compatible with the MRI environment. Two generations of optical limit switches are designed to provide better safety features for real clinical use. The performance of both generations of the limit switch is tested. MRI guided accuracy and MRI-compatibility of whole robotic system is also evaluated. Two clinical prostate biopsy cases have been conducted with this assistive robot.
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DEVELOPMENT OF A FORCE SENSING INSOLE TO QUANTIFY IMPACT LOADING TO THE FOOT IN VARIOUS POSTURES / A FORCE SENSING INSOLE TO QUANTIFY IMPACT LOADING TO THE FOOTVan Tuyl, John T. January 2014 (has links)
Lower leg injuries commonly occur in both automobile accidents and underbody explosive blasts, which can be experienced in war by mounted soldiers. These injuries are associated with high morbidity. Accurate methods to predict these injuries, especially in the foot and ankle, must be developed to facilitate the testing and improvement of vehicle safety systems.
Anthropomorphic Test Devices (ATDs) are one of the tools used to assess injury risk. These mimic the behavior of the human body in a crash while recording data from sensors in the ATD. Injury criteria for the lower leg have been developed with testing of the leg in a neutral posture, but initial posture may affect the likelihood of lower leg injury.
In this thesis, the influence of initial posture on key injury assessment criteria used in crash testing with ATDs was examined. It was determined that these criteria are influenced by ATD leg posture, but further work is necessary to determine if the changes in outcome correspond to altered injury risk in humans when the ankle is in the same postures.
In order to better quantify the forces acting on various areas of the foot and correlate those with injury, allowing for development of new criteria, a purpose built force sensor was created. An array of these sensors was incorporated into a boot and used to instrument an ATD leg during impact testing. The sensors provided useful information regarding the force distribution across the sole of the foot during an impact. A numerical simulation of the active material in the sensor was also created to better understand the effect of shear loading on the sensor.
This work furthers the understanding of lower leg injury prediction and develops a tool which may be useful in developing accurate injury criteria for the foot and lower leg. / Thesis / Master of Applied Science (MASc) / This work investigates how the posture of the lower leg of a crash test dummy can influence the interpretation of crash test results. A tool was created to measure forces acting on the foot during testing. The force measurement uses a material which changes resistance when it is compressed.
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Advanced Force Sensing and Novel Microrobotic Mechanisms for Biomedical ApplicationsGeorges Adam (13237722) 12 August 2022 (has links)
<p>Over the years, research and development of micro-force sensing techniques has gained a lot of traction, especially for microrobotic applications, such as micromanipulation and biomedical material characterization studies. Moreover, in recent years, new microfabrication techniques have been developed, such as two-photon polymerization (TPP), which enables fast prototyping, high resolution features, and the utilization of a wide range of materials. In general, the main goals of this work are to improve the resolution and range of novel vision-based force sensors, create microrobotic and micromanipulation systems capable of tackling a multitude of applications, and ensuring these systems are flexible and provide a sold foundation to the advancement of the field as a whole.</p>
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<p>The current work can be divided into three main parts: (i) a wireless magnetic microrobot with 2D vision-based force sensing, (ii) a 3D vision-based force sensing probe for tethered micromanipulators, and (iii) a micromanipulation system capable of accurately controlling and performing advanced tasks. The vision-based force sensors developed here have resolutions ranging from the mN range to even sub-$\mu$N range, depending on the material used, geometry, and overall footprint. </p>
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<p>In part (i), the microrobot has been developed mainly for biomedical applications \textit{in vitro}, with the ability to perform mechanical characterization and microassembly tasks of different rigid and biomedical materials. In part (ii), a similar sensor mechanic is used, but now adapted to a micromanipulation probe, which is able to detect forces in three dimensions and work in dry environments. In conjunction with the micromanipulation system described in part (iii), the system is capable of performing advanced assembly applications, including accurate assembly and 3D mounting of microparts. </p>
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<p>With the introduction of TPP technologies to these works, the next generation of adaptable microrobotics and micromanipulation systems for advanced biomedical applications is starting to take shape, ever more versatile, smaller, more accurate, and with more advanced capabilities. This work shows the progression of these overall systems and gives a glimpse of what is possible with TPP and the technologies to come.</p>
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Estudo e desenvolvimento de sistema baseado em sensores de pressão aplicados à ortodontiaCrivellaro, Fernando Sacilotto January 2016 (has links)
Este trabalho tem por objetivo o estudo e o desenvolvimento de uma solução de engenharia para o mapeamento e caracterização da oclusão dentária, não somente no âmbito de sua distribuição ao longo da arcada, mas também através da mensuração da intensidade de pressão nos pontos de contato oclusal interarco. Neste sentido, empregaram-se esforços no aprofundamento do conhecimento neste campo da Odontologia, assim como, na elaboração de um sistema experimental que, utilizando sensores de pressão/força resistivos (FSR) específicos para uso odontológico, viabilizou a análise do estado da oclusão, atuando como agente facilitador no diagnóstico de desequilíbrios oclusais. Inicialmente, são apresentados e esclarecidos os principais conceitos da esfera odontológica, os quais são tomados como base para todos os projetos deste trabalho, além da abordagem referente às formas de contato entre os dentes, aos diferentes tipos de oclusão e seus problemas. Em relação ao desenvolvimento do sistema, foram projetadas duas placas de circuito impresso para interface com os sensores e elaborados o firmware de acesso ao hardware, assim como o software de gerenciamento global do sistema. Todos os blocos do circuito de condicionamento foram avaliados e as suas funcionalidades validadas. Do mesmo modo, a caracterização da resposta dos sensores e a sua homogeneidade ao longo da extensão sensível foram analisadas, demonstrando que a resistência elétrica varia de forma análoga em todas as áreas do sensor. Através de ensaios realizados com sujeito envolvido no projeto, estabeleceu-se um comparativo entre a utilização do papel carbono e o sistema desenvolvido, mostrando as vantagens na utilização do segundo, principalmente atreladas à capacidade de avaliação da intensidade dos contatos oclusais. Por fim, ainda se valendo do uso paralelo do papel carbono, foram efetuados ensaios de análise da oclusão em sujeito envolvido no projeto utilizando placa miorrelaxante, possibilitando a utilização da capacidade do sistema desenvolvido para executar ajustes precisos na placa, com a finalidade de manter o balanço de pressões oclusais entre ambos os lados da arcada. / This essay has as objective the study and development of an engineer solution for the dental occlusion mapping and characterization, not only related to the interarch occlusal contact distribution, but also through the pressure magnitude measuring in each. In this sense, was employed effort in the Odontological knowledge increasing and also in the system elaboration allowing the occlusion state evaluation and acting as an easier agent in the occlusion disturbs diagnosing using a specific pressure/force sensing resistor (FSR) for dental use. Initially the main concepts of the Odontological sphere are presented, clarified and took as a base for all the projects in this essay. Besides this, different teeth contacts shapes are shown, as well as the occlusion’s types and its problems. In the system development, two printed circuit boards were designed for sensor interfacing. The hardware access through the firmware was elaborated, even as the global system managing software. All the conditioning circuit blocks and functionalities were evaluated and validated. In the same way, the sensor’s output and its homogeneity through all the sensible extension were evaluated, showing that the sensor’s electric resistance changes in the same form in all the sensor’s areas. In addition, it was showed the advantages of the developed system over the articulation paper through trials with a subject that is part of the project, showing the capacity of the system in the occlusion contacts magnitude evaluation. Ultimately, also in an articulation paper versus the developed system comparison, it was made occlusion analysis trials with subject using a night guard for teeth grinding (bruxism), showing the system capacity of precisely adjust the night guards for pressure balance between the both arch sides.
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Estudo e desenvolvimento de sistema baseado em sensores de pressão aplicados à ortodontiaCrivellaro, Fernando Sacilotto January 2016 (has links)
Este trabalho tem por objetivo o estudo e o desenvolvimento de uma solução de engenharia para o mapeamento e caracterização da oclusão dentária, não somente no âmbito de sua distribuição ao longo da arcada, mas também através da mensuração da intensidade de pressão nos pontos de contato oclusal interarco. Neste sentido, empregaram-se esforços no aprofundamento do conhecimento neste campo da Odontologia, assim como, na elaboração de um sistema experimental que, utilizando sensores de pressão/força resistivos (FSR) específicos para uso odontológico, viabilizou a análise do estado da oclusão, atuando como agente facilitador no diagnóstico de desequilíbrios oclusais. Inicialmente, são apresentados e esclarecidos os principais conceitos da esfera odontológica, os quais são tomados como base para todos os projetos deste trabalho, além da abordagem referente às formas de contato entre os dentes, aos diferentes tipos de oclusão e seus problemas. Em relação ao desenvolvimento do sistema, foram projetadas duas placas de circuito impresso para interface com os sensores e elaborados o firmware de acesso ao hardware, assim como o software de gerenciamento global do sistema. Todos os blocos do circuito de condicionamento foram avaliados e as suas funcionalidades validadas. Do mesmo modo, a caracterização da resposta dos sensores e a sua homogeneidade ao longo da extensão sensível foram analisadas, demonstrando que a resistência elétrica varia de forma análoga em todas as áreas do sensor. Através de ensaios realizados com sujeito envolvido no projeto, estabeleceu-se um comparativo entre a utilização do papel carbono e o sistema desenvolvido, mostrando as vantagens na utilização do segundo, principalmente atreladas à capacidade de avaliação da intensidade dos contatos oclusais. Por fim, ainda se valendo do uso paralelo do papel carbono, foram efetuados ensaios de análise da oclusão em sujeito envolvido no projeto utilizando placa miorrelaxante, possibilitando a utilização da capacidade do sistema desenvolvido para executar ajustes precisos na placa, com a finalidade de manter o balanço de pressões oclusais entre ambos os lados da arcada. / This essay has as objective the study and development of an engineer solution for the dental occlusion mapping and characterization, not only related to the interarch occlusal contact distribution, but also through the pressure magnitude measuring in each. In this sense, was employed effort in the Odontological knowledge increasing and also in the system elaboration allowing the occlusion state evaluation and acting as an easier agent in the occlusion disturbs diagnosing using a specific pressure/force sensing resistor (FSR) for dental use. Initially the main concepts of the Odontological sphere are presented, clarified and took as a base for all the projects in this essay. Besides this, different teeth contacts shapes are shown, as well as the occlusion’s types and its problems. In the system development, two printed circuit boards were designed for sensor interfacing. The hardware access through the firmware was elaborated, even as the global system managing software. All the conditioning circuit blocks and functionalities were evaluated and validated. In the same way, the sensor’s output and its homogeneity through all the sensible extension were evaluated, showing that the sensor’s electric resistance changes in the same form in all the sensor’s areas. In addition, it was showed the advantages of the developed system over the articulation paper through trials with a subject that is part of the project, showing the capacity of the system in the occlusion contacts magnitude evaluation. Ultimately, also in an articulation paper versus the developed system comparison, it was made occlusion analysis trials with subject using a night guard for teeth grinding (bruxism), showing the system capacity of precisely adjust the night guards for pressure balance between the both arch sides.
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