Modeling and Control of Active Cochlear Implant - CRISTAL-DEFROST
Thèse Année : 2024

Modeling and Control of Active Cochlear Implant

Modélisation et Commande de L'implant Cochléaire Active

Lingxiao Xun

Résumé

According to the statistic of World Health Organization, over 5% of the world's population, i.e., 360 million people, has disabling hearing loss (328 million adults and 32 million children). Hearing aids are quite successfully used for the partially deafened people. Traditional hearing aids, while effective for partial hearing loss, often fall short for individuals with severe deafness. In such cases, cochlear implant surgery emerges as a preferable solution. Traditional manual implantation, however, grapples with the complexities of human anatomy and procedural intricacies. Among the primary challenges are the risks of damaging sensitive structures like the facial nerve and the propensity of the electrode array to bend within the cochlea, impeding complete implantation. Despite precision in manual techniques, the limited visibility and heavy reliance on the surgeon's steadiness and expertise inherently carry risks.

Robot-assisted cochlear implant surgery signifies a major breakthrough in otolaryngology, aiming to heighten the precision and effectiveness of these procedures. This innovative approach, featuring an active electrode array, addresses the limitations of traditional surgery. The distinguishing aspect of active cochlear implants is their self-adjusting electrode array, which adapts during implantation to align perfectly with the cochlea's complex spiral path. This feature not only boosts implant efficacy but also minimizes potential complications.

Present research in cochlear implant technology concentrates on refining mechanical models and improving control systems for implantation. Conventional finite element models, while standard for simulating cochlear implant mechanics, struggle with real-time simulation and responsive control due to their high-dimensional complexity. Accurately determining physical parameters is another major challenge, affecting both the precision of simulations and the effectiveness of control methods. Therefore, there is a pressing need for models that are both precise and computationally efficient, alongside advanced control systems capable of adapting to the dynamic nature of implantation.

This thesis contributes significantly in three areas. First, it introduces a novel electronic and mechanical model for the cochlear implant's electrode array, employing Cosserat rod theory. This model, in contrast to traditional finite element models, offers similar accuracy with reduced complexity, thereby enabling real-time simulation and control during implantation. Its reduced computational demands make it more viable for clinical application, and its effectiveness has been corroborated through detailed simulations and experiments. Second, the study innovates in parameter identification by integrating a visual system to measure actuator curvature, thereby deriving physical parameters through a novel nonlinear electro-mechanical coupling model. Lastly, the thesis's crowning achievement is the development of an optimal control system based on the new electro-mechanical model. This system, founded on contact mechanics models, enables advanced multi-drive coupled trajectory tracking control. Rigorous testing through experiments and simulations confirms its robustness and reliability, marking a step forward in enhancing precision and safety in cochlear implant procedures.

Selon les statistiques de l'Organisation Mondiale de la Santé, plus de 5\% de la population mondiale, soit 360 millions de personnes, souffre de pertes auditives invalidantes. Les aides auditives traditionnelles ne sont généralement pas suffisantes pour ceux atteints de surdité sévère, rendant la chirurgie d'implant cochléaire une meilleure solution. Cependant, l'implantation manuelle traditionnelle est confrontée à des défis dus à la complexité de l'anatomie humaine et aux détails procéduraux, tels que le risque de dommages au nerf facial et la tendance de l'array d'électrodes à se courber dans la cochlée. Pour résoudre ces problèmes, cette thèse propose un nouveau modèle électronique et mécanique utilisant la théorie des tiges de Cosserat, qui réduit la complexité et améliore la simulation et le contrôle en temps réel par rapport aux modèles traditionnels à éléments finis. La recherche innove également dans l'identification des paramètres en intégrant un système visuel pour mesurer la courbure de l'actuateur, dérivant ainsi les paramètres physiques à travers un nouveau modèle de couplage électro-mécanique non linéaire. De plus, nous développons un système de contrôle optimisé basé sur le nouveau modèle électro-mécanique. Des tests rigoureux par des expériences et des simulations ont prouvé son efficacité pour améliorer la précision et la sécurité des chirurgies d'implant cochléaire.
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Dates et versions

tel-04803737 , version 1 (25-11-2024)

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Lingxiao Xun. Modeling and Control of Active Cochlear Implant. Engineering Sciences [physics]. Centrale Lille, 2024. English. ⟨NNT : 2024CLIL0005⟩. ⟨tel-04803737⟩
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