Type of thesis
ORTEGA ALCAIDE, JOAN
Magnetically-driven robotic capsule navigation for colonoscopic procedures
Scientific disciplinary sector
Istituto di Biorobotica - BIOROBOTICS
relatore Prof. DARIO, PAOLO
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Exam session start date
Soft-tethered magnetic capsules have the potential to become the gold standard for diagnosing colorectal cancer; thus, simplifying and reducing the risk and discomfort of traditional colonoscopy. To ensure that the magnetic forces and torques applied on the capsule are safe<br>for the patient and sufficient to translate the capsule, the interaction between the colon and the soft-tethered magnetic capsule must be better understood. Additionally, existing magnetic navigation control frameworks need further development to account for realistic in vivo conditions while maintaining clinically acceptable procedure times.<br><br>The first aim of this work is to develop a magnetic robotic platform to experimentally test magnetic navigation strategies under realistic ex vivo scenarios. The second aim is to characterize the resistance to overcome when pulling a soft-tethered capsule along the colon. Finally, the last aim is to present various control frameworks which enable the soft-tethered capsule to navigate the colon in a robust, safe, and rapid manner.<br><br>This work presents an analytical model, validated in ex vivo conditions, for the resistance forces introduced by the tether-colon interaction. Such forces are the main resistance to overcome during navigation and grow exponentially as a function of the friction coefficient and the contact angle. Additionally, we demonstrate that a tangential space force control framework allows for a more reactive navigation. A set of robot motion primitives are presented which maximize the local increase in navigation force by accounting for the effect magnetic forces have on the capsule-colon interaction resistance. The motion primitives overcome previously impregnable realistic scenarios while reducing the stress on the colon walls.<br><br>These findings suggest that the resistance introduced by the tether must be reduced and that the novel motion primitives have the potential to allow for effective in-vivo navigation.
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