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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.
1

A System For Automated Vision-guided Suturing

Iyer, Santosh 15 November 2013 (has links)
Suturing in laparoscopic surgery is a challenging and time-consuming task that presents haptic, motor and spatial constraints for the surgeon. As a result, there is variability in surgical outcome when performing basic suturing tasks such as knot tying, stitching and tissue dissection (as large as 50\%). This goal of this thesis is to develop a standardized, proof-of-concept, automated robotic suturing system that performs a side-to-side anastomosis with image guidance and dynamic trajectory control. A passive alignment tool is created for rigidly constraining needle pose, and robust computer vision algorithms are used to track surface features and the suture needle. A robotic system integrates these components to autonomously pass a curved suture needle through sequential loops in a tissue pad phantom.
2

A System For Automated Vision-guided Suturing

Iyer, Santosh 15 November 2013 (has links)
Suturing in laparoscopic surgery is a challenging and time-consuming task that presents haptic, motor and spatial constraints for the surgeon. As a result, there is variability in surgical outcome when performing basic suturing tasks such as knot tying, stitching and tissue dissection (as large as 50\%). This goal of this thesis is to develop a standardized, proof-of-concept, automated robotic suturing system that performs a side-to-side anastomosis with image guidance and dynamic trajectory control. A passive alignment tool is created for rigidly constraining needle pose, and robust computer vision algorithms are used to track surface features and the suture needle. A robotic system integrates these components to autonomously pass a curved suture needle through sequential loops in a tissue pad phantom.
3

Control of meso-robots for endoluminal surgery / Contribution à la commande de méso-robots pour la chirurgie endoluminale

Sánchez Secades, Luis Alonso 30 August 2013 (has links)
Cette thèse porte sur la conception et la validation expérimentale d’une architecture de téléopération avec retour d’effort pour la chirurgie endoluminale. Dans cette perspective, un robot chirurgical, à échelle mésoscopique, a été utilisé en tant que dispositif téléopéré. Ce robot, nommé SPRINT, a été développé dans le cadre du projet Européen ARAKNES (FP7, bourse no. 224565). L’objectif de ce projet, est d’insérer les degrés de liberté robotisés nécessaires aux manipulations chirurgicales à l’intérieur de la cavité péritonéale, ce qui permet d’apporter une assistance active durant la chirurgie laparoscopique à trocart unique. Pour répondre à cette problématique, plusieurs études ont été menées. Tout d’abord, une analyse détaillée du processus de conception des robots chirurgicaux a été réalisée, afin de garantir le transfert des technologies issues de la recherche vers le bloc opératoire. Puis, la mise en œuvre d’une architecture logicielle générique et temps réel a été décrite, servant de base au système actuel. Ce dernier est constitué d’un contrôleur adaptatif qui utilise un observateur d’état actif (AOB) ainsi qu’un modèle viscoélastique de tissus mous du type Kelvin- Boltzmann. Une telle association permet d’améliorer les performances du système de téléopération par rapport aux contributions précédentes qui utilisaient des modèles moins réalistes de tissus, tel que le modèle élastique. Dans ce contexte, deux schémas de téléopération de type “position-position” et “position-force” ont été proposés afin de répondre aux contraintes matérielles de la plateforme ARAKNES. La transparence et la stabilité, i.e. les deux paramètres qui permettent de quantifier les performances des systèmes téléopérés, des schémas proposés ont été étudiées. De plus, les effets d’une mise à l’échelle des positions qui sont commandées par le chirurgien, ainsi que des efforts ressentis par ce dernier, ont été examinés du point de la performance du système téléopéré. Enfin, la possibilité d’effectuer une commande sans-fil des robots chirurgicaux a été aussi abordée afin d’augmenter les libertés de mouvement des méso-robots et d’explorer les possibilités d’amélioration en termes de performance mécanique et de miniaturisation. / This dissertation deals with the design, implementation and experimental validation of a force-reflecting teleoperation architecture for robotic assisted endoluminal surgery. For this purpose, a meso-scale surgical robot was used as target device to be teleoperated. This robot, codenamed SPRINT, was developed during the ARAKNES European project (FP7, grant agreement no. 224565). The key idea of ARAKNES was to transfer the robot’s degrees of freedom required for surgery inside the peritoneal cavity, allowing to provide robotic assistance in single port laparoscopic surgery. In order to attain the objectives of this work, several studies were carried out : First, the specifics of surgical robotic design were investigated with the objective of guar- anteeing the technology transfer from research centers into the operating room. Second, a generic real-time software architecture for surgical robots was described, serving as support for the current implementation of the teleoperation control system. The latter system employs an adaptive controller which is based on an active state observer (AOB) and a viscoelastic Kelvin-Boltzmann soft-tissue environment model. This com- bination allows improving the performance with respect to previous works in the field that use less realistic soft-tissue environment models, such as the elastic model. In this context, two teleoperation schemes of types “position–position” and “position–force” were proposed in order to fulfill the hardware requirements of ARAKNES. Both schemes were analyzed in terms of their transparency and stability, i.e. the two parameters that allow quantifying the performance of teleoperated systems. Furthermore, the effects of scaling the po- sitions and the forces which are respectively commanded and felt by the surgeon, were examined regarding the surgeon’s performance, and also the system’s performance. Finally, the possibility of performing wireless control of surgical robots was also explored in order to increase the freedom of movement and, possibly, to improve the mechanical performance and/or miniaturization of the surgical robots that were employed.
4

Compact and Low-Cost Acoustic-Resolution Photoacoustic Microscopy Based on Delta Configuration Actuator

Gao, Shang 15 May 2020 (has links)
Photoacoustic (PA) Imaging is an emerging biomedical imaging modality based on the laser-generated ultrasound. The method has unique advantages in providing microvessel structure visualization, neuroimaging, and functional imaging provided by its physical principle. Photoacoustic microscopy (PAM) is one of the PA imaging instruments which provides high resolution and contrast imaging of a near-field target. Relying on the acoustic focusing, Acoustic-resolution PAM (AR-PAM) is capable of reaching a sub-centimeter of penetration depth with sub-millimeter resolution and is optimized for tissue samples and small animals. However, the state-of-art AR-PAMs are large in size and expensive in cost, which hinders its democratization. There are previous researches conducted on reducing the cost by introducing a low-cost optical source or ultrasound acquisition device. Few research has investigated the possibility of modification on actuator design. The total system cost should be further reduced by substituting the translation stage while maintaining the imaging quality. In this research, a delta configuration actuation is introduced to the AR-PAM. The delta-configuration actuation adapted from a low-cost off-the-shelf 3D printer has been implemented in the design. An economical PAM system that integrates the combination of hardware and software enhancement is designed and tested in this research. With the software approach, advanced beamforming methods such as Delay-and-Sum with Coherence Factor (DAS+CF) and Delay-Multiply-and-Sum (DMAS) algorithms are applied to obtaining the high-resolution PA image through 3D reconstruction. The preliminary phantom study demonstrated the applicability of low-cost delta configuration actuators for AR-PAM imaging. The simulation study shows the beamforming algorithms has capability to remove the device precision error and increasing the tolerance. The research suggests that the 3D reconstruction algorithms significantly improve the resolution and contrast of the image quality.
5

Towards Naturalistic Exoskeleton Glove Control for Rehabilitation and Assistance

Chauhan, Raghuraj Jitendra 11 January 2020 (has links)
This thesis presents both a control scheme for naturalistic control of an exoskeleton glove and a glove design. Exoskeleton development has been focused primarily on design, improving soft actuator and cable-driven systems, with only limited focus on intelligent control. There is a need for control that is not limited to position or force reference signals and is user-driven. By implementing a motion amplification controller to increase weak movements of an impaired individual, a finger joint trajectory can be observed and used to predict their grasping intention. The motion amplification functions off of a virtual dynamical system that safely enforces the range of motion of the finger joints and ensures stability. Three grasp prediction algorithms are developed with improved levels of accuracy: regression, trajectory, and deep learning based. These algorithms were tested on published finger joint trajectories. The fusion of the amplification and prediction could be used to achieve naturalistic, user-guided control of an exoskeleton glove. The key to accomplishing this is series elastic actuators to move the finger joints, thereby allowing the wearer to deflect against the glove and inform the controller of their intention. These actuators are used to move the fingers in a nine degree of freedom exoskeleton that is capable of achieving all the grasps used most frequently in daily life. The controllers and exoskeleton presented here are the basis for improved exoskeleton glove control that can be used to assist or rehabilitate impaired individuals. / Master of Science / Millions of Americans report difficulty holding small or even lightweight objects. In many of these cases, their difficulty stems from a condition such as a stroke or arthritis, requiring either rehabilitation or assistance. For both treatments, exoskeleton gloves are a potential solution; however, widespread deployment of exoskeletons in the treatment of hand conditions requires significant advancement. Towards that end, the research community has devoted itself to improving the design of exoskeletons. Systems that use soft actuation or are driven by artificial tendons have merit in that they are comfortable to the wearer, but lack the rigidity required for monitoring the state of the hand and controlling it. Electromyography sensors are also a commonly explored technology for determining motion intention; however, only primitive conclusions can be drawn when using these sensors on the muscles that control the human hand. This thesis proposes a system that does not rely on soft actuation but rather a deflectable exoskeleton that can be used in rehabilitation or assistance. By using series elastic actuators to move the exoskeleton, the wearer of the glove can exert their influence over the machine. Additionally, more intelligent control is needed in the exoskeleton. The approach taken here is twofold. First, a motion amplification controller increases the finger movements of the wearer. Second, the amplified motion is processed using machine learning algorithms to predict what type of grasp the user is attempting. The controller would then be able to fuse the two, the amplification and prediction, to control the glove naturalistically.
6

DEVELOPMENT OF A SOFT HAND EXOSKELETON FOR HAND REHABILITATION

Jose Alfredo Ocegueda Barraza (14237807) 09 December 2022 (has links)
<p>  </p> <p>To regain a healthy degree of hand function, injured patients require strenuous rehabilitation therapies with the expectation of gaining the full range of motion and strength necessary for performing activities of daily living (ADLs). Metacarpal fractures are one of the most common musculoskeletal injuries and require occupational therapy after the immobilization phase. Obstacles, such as longer recovery times, high costs, or lack of trained physiotherapists, often present a barrier for individuals seeking adequate treatment. Repetitive extension and flexion therapy routines improve grasping functionalities when performed correctly and repetitively. Robotic devices, such as hand exoskeletons, have been found to make up for the lack of hand motor function and assist in grasping tasks performed in ADLs, improving users’ independence. To increase robot acceptability, wearable robots have been recently proposed as part of rehabilitation technologies. Hand rehabilitation systems are an active research interest; however, most studies focus on rehabilitating central nerve injuries. There is a lack of research on systems treating hand fracture injuries, explicitly focusing on function recovery involving the fingers. Integrating systems that provide the necessary dexterity in a user-friendly manner while keeping a compact and lightweight fashion remains challenging. This thesis describes the development of a Soft Hand Exoskeleton (SHE) for robotic hand rehabilitation. The system integrates a flexible glove-like body and a bio-inspired cable-driven transmission system for motion assistance. The exoskeleton’s usage effects were evaluated through a user study experiment. An electromyography (EMG) based analysis allowed us to assess the muscular effort demands of ADLs. Experimental results and evaluation metrics demonstrated a reduction in the total integrated muscular activity (TIMA) in the performance of common ADLs when wearing the SHE system. </p>
7

Semi-Robotic Knee Arthroscopy System with Braking Mechanism

Hua, Thai 01 January 2023 (has links) (PDF)
To alleviate the poor ergonomics which surgeons suffer during knee arthroscopy, a semi-robotic device with braking mechanism is created for intraoperative assistance. A slitted ball joint assembly is developed to transmit the clamping force to the arthroscope inside. Ball deformation and stress at various angles to the vertical and clamping forces is recorded through Abaqus Finite Element Analysis (FEA). Contact forces between the scope and inner surfaces of the ball is also computed in FEA at different clamping forces. The von Mises stress occurring in the ball joint is under the yield stress limit for polyethylene, and there is noticeable force preventing the scope from sliding along the ball through-hole under clamping. A prototype of this device is constructed for proof-of-concept.
8

Model based force control for soft tissue interaction and applications in physiological motion compensation / Asservissement en effort pour des interactions avec des tissus mous et applications pour la compensation de moviments physiologiques

Lopes da Frota Moreira, Pedro 13 December 2012 (has links)
L'introduction de systèmes robotisés dans les salles opératoires a fait évoluer la chirurgie moderne, ouvrant aux chirurgiens de nouvelles possibilités. La présence de tels systèmes en salle opératoire croît chaque année. Les progrès des robots médicaux sont étroitement liés au développement de nouvelles techniques permettant de mieux contrôler les interactions entre la machine et les tissus biologiques. L'objectif principal de cette thèse est de proposer une commande en force basée sur un modèle, conçue pour améliorer la stabilité et la robustesse du contrôle en vue d'applications médicales. Une étude sur la modélisation des tissus mous ainsi que le choix d'un modèle compatible temps-réel sont présentés. Après cette analyse, le modèle de Kelvin Boltzmann a été choisi et implémenté dans le schéma de contrôle en force proposé, basé sur des observateurs actifs. La stabilité et la robustesse de la commande sont analysées en théorie et au travers d'expérimentations. Les performances de la commande en force sont également mesurées, en tenant compte des perturbations dues aux mouvements physiologiques. Finalement, afin d'améliorer la qualité du rejet des perturbations, une boucle de commande supplémentaire est ajoutée au moyen d'une estimation des perturbations basée sur le modèle de Kelvin Boltzmann et des séries de Fourier. / The introduction of robotic systems inside the operating room has changed the modern surgery, opening new possibilities to surgeons. The number of robotic systems inside the operation room is increasing every year. The progress of medical robots are associated to the development of new techniques to better control the interaction between the robot and living soft tissues. This thesis focus on the development of a model based force control designed to improve stability and robustness of force control addressed to medical applications. A study of soft tissue modeling is presented and a suitable model to be used in a real-time control is selected. After the analysis, the Kelvin Boltzmann model was chosen to be inserted in the proposed force control scheme based on Active Observers. Stability and robustness are theoretically and experimentally analyzed. The performance of the proposed force control is also investigated under physiological motion disturbances. At the end, to improve the disturbance rejection capability, an extra control loop is added using a disturbance estimation based on the Kelvin Boltzmann model and a Fourier series.
9

Suivi 3D Robuste pour la Chirurgie Cardiaque Robotisée / Robust 3D Motion Tracking for Robotic-Assisted Beating Heart Surgery

Richa, Rogério de Almeida 23 March 2010 (has links)
Les dernières décennies ont vu le développement important de la chirurgie mini-invasive. L'acte mini-invasif apporte de nombreux avantages pour les patients: séjour plus court à l'hôpital, réduction des coûts, un traumatisme réduit et la diminution des complications postopératoires. Dans ce contexte, l'assistance robotique est capable de rendre l'acte chirurgical plus intuitif et plus sûr pour les chirurgiens. Dans le domaine de la chirurgie cardiaque mini-invasive, les mouvements respiratoires et cardiaques sont deux sources de perturbations importantes pour les chirurgiens. Malgré l'existence de versions miniaturisées de stabilisateurs cardiaques mécaniques, le mouvement résiduel est encore considérable et doit être manuellement compensé par le chirurgien. Dans ces travaux de thèse, des techniques de suivi visuel pour l'estimation du mouvement 3D du coeur ont été développées. Pour la compensation active des mouvements physiologiques, seules les structures naturelles sur la surface du coeur sont utilisées. Deux contributions dans le domaine de la compensation des mouvements physiologiques pour la chirurgie cardiaque robotisée ont été proposées. La première est une méthode de suivi visuel 3D basée sur un modèle déformable de type ``plaque mince'' et une paramétrisation efficace pour le suivi 3D en images stéréo-endoscopiques. La seconde contribution est une méthode de suivi robuste qui prédit le mouvement futur du coeur pour contourner des problèmes comme les occlusions par les instruments chirurgicaux et les éventuelles réflexions spéculaires. La méthode de prédiction est basée sur une série de Fourier estimée à travers un filtre de Kalman étendu. / The past decades have witnessed the notable development of minimally invasive surgery (MIS). The benefits of this modality of surgery for patients are numerous, shortening convalescence, reducing trauma and surgery costs. In this context, robotic assistance aims to make the surgical act more intuitive and safer. In the domain of cardiac MIS, heartbeat and respiration represent two important sources of disturbances. Even though miniaturized versions of heart stabilizers have been conceived for the MIS scenario, residual motion is still considerable and has to be manually canceled by the surgeon. In this thesis, the focus is put on computer vision techniques for estimating the 3D motion of the heart relying solely on natural structures on the heart surface for active compensation of physiological motions. Two main contributions on the subject of motion compensation for robotized cardiac MIS are proposed. The first is a visual tracking method for estimating the 3D deformation of a region of interest on the heart surface. A thin-plate spline model is used for representing the heart surface deformations and a novel efficient parameterization for 3D tracking using stereo endoscopic images is proposed. The method is robust to illumination variations and large tissue deformations. The second contribution is a robust visual tracking method using motion prediction. A time-varying dual Fourier series for modeling the quasi-periodic beating heart motion is proposed. For estimating the parameters of the Fourier series, a probabilistic framework is based on the Extended Kalman filter (EKF) is used. The visual tracking method is integrated in the heart motion prediction framework, creating an unified framework for estimating the temporal motion and spatial deformation of the heart surface. Experimental results have shown the effectiveness of the proposed methods.
10

Haptic Teleoperation for Robotic-Assisted Surgery / Téléopération avec retour haptique pour chirurgies assistées par robot

Albakri, Abdulrahman 16 December 2015 (has links)
Dans ce travail de thèse, nous examinons les principaux facteurs affectant la transparence d'un schéma de téléopération dans le contexte de la robotique médicale.Afin de déterminer ces facteurs, une analyse approfondie de l'état de l'art a été réalisée ce qui a permis de proposer une nouvelle classification de schémas de téléopération avec retour haptique.Le rôle de ces principaux facteurs a été analysé.Ces facteurs sont liés à l'architecture de commande appliquée, aux perturbations provoquées par les mouvements physiologiques des tissus manipulés ainsi qu'à la précision du modèle d'interaction robot-tissue.Les performances du schéma de téléopération à architecture 3-canaux ont été analysées en simulation pour choisir une architecture de commande dédiée aux applications médicales.Ensuite, l'influence des mouvements physiologiques de l'environnement manipulé sur la transparence du système a été analysée et un nouveau modèle d'interaction avec des tissus mous a été proposé.Un schéma de commande de téléopération basé modèle d'interaction a été proposé en se basant sur une analyse de passivité du port d'interaction robot-environnement.Enfin, l'importance de la précision du modèle d'interaction (robot-tissue) sur la transparence du schéma de téléopération avec retour d'effort basé-modèle a été analysée.Cette analyse a été validée en théorie et expérimentalement en implémentant le modèle Hunt-Crossly dans une commande utilisant un AOB pour réaliser une téléopération avec retour haptique.En conclusion de ce travail, les résultats de cette thèse ont été discutés et les perspectives futures ont également été proposées. / This thesis investigates the major factors affecting teleoperation transparency in medical context.A wide state of art survey is carried out and a new point of view to classify haptic teleoperation literature is proposed in order to extract the decisive factors providing a transparent teleoperation.Furthermore, the roles of three aspects have been analysed.First, The role of the applied control architecture.To this aim, the performances of 3-channel teleoperation are analysed and guidelines to select a suitable control architecture for medical applications are proposed.The validation of these guidelines is illustrated through simulations.Second, the effects of motion disturbance in the manipulated environment on telepresence are analysed.Consequently, a new model of such moving environment is proposed and the applicability of the proposed model is shown through interaction port passivity investigation.Third analysed factor is the role of the interaction model accuracy on the transparency of interaction control based haptic teleoperation.This analysis is performed theoretically and experimentally by the design and implementation of Hunt-Crossly in AOB interaction control haptic teleoperation.The results are discussed and the future perspectives are proposed.

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