Modelling and Control of a Tendon-Driven Steerable Sheath

Percutaneous left atrial appendage closure (LAAC) procedures can reduce the risk of stroke for patients with atrial fibrillation by implanting a closure device inside the left atrial appendage (LAA) by means of a pre-curved or steerable sheath. However, the most frequently encountered challenge in these procedures is suboptimal device implantation due to anatomical variability. To address these challenge research is focusing on enhancing LAAC procedures by developing advanced technical solutions, including robotic systems. This thesis aims to develop a mathematical model and a control strategy for a novel robotic tendon-driven steerable sheath for LAAC, to enable precise positioning of the closure device within the LAA. For the purpose of this thesis, a piecewise constant curvature model was developed to describe the kinematics of the steerable sheath, along with the realization of an open-loop control strategy. Additionally, a graphical user interface was created to interact with the robotic system, incorporating features such as switching between automatic and manual control modes, thereby providing flexibility in a shared control environment. To evaluate the performance of the system, bench tests were conducted to assess the precision of the robot's modelling and control framework, while usability tests were carried out to examine the effectiveness of the graphical interface. The final outcome successfully demonstrated the performance and control of the robotic system, achieving precise and reliable operation in a shared control environment.