Loading...
Autonomous control of magnetic continuum devices for surgical applications
Pratt, Richard L.
Pratt, Richard L.
Citations
Altmetric:
Advisor
Editor
Date
Date Issued
2023
Date Submitted
Collections
Research Projects
Organizational Units
Journal Issue
Embargo Expires
2024-04-18
Abstract
Enabling continuum devices to autonomously execute complex trajectories with closed-loop control can improve surgical outcomes in numerous clinical interventions including deep brain stimulation and cardiac ablation. In Chapter 2 we derive a physically motivated kinematic model for an actively steered magnetic-tipped needle. Noise and model parameters are identified using an expectation-maximization algorithm. Experimental results compare this derived model to the established bicycle needle model, and find our derived model to be preferred for modeling soft brain tissue needle insertion.
In Chapter 3, our physically motivated kinematic model is used in closed-loop control to follow a target insertion trajectory. The applied control law is derived using Lyapunov redesign. Simulation results demonstrate the robustness of the control implementation for a wide range of conditions. Control is performed experimentally in a brain tissue phantom for both initial position offset recovery and curved trajectories. Converged error results average 0.52 mm from target trajectory, which exceeds the 2 mm accuracy required for the target application. This work also has implications in general vehicle steering. Both the model and control can apply to systems with similar kinematics such as watercraft and wheeled vehicles that could benefit from a relaxed slip constraint.
Chapter 4 demonstrates closed-loop control of an extensible catheter with an embedded magnet at its distal tip. We implement a control method coined observed control to perform model-based predictive control of the magnetic catheter using a Kalman smoother framework. Using this same smoother framework, we also solve for catheter shape and orientation given magnetic and insertion control using Cosserat rod theory, and implement a disturbance observer for closed-loop control. A 3D cube trajectory was traversed with the catheter tip with average experimental positional accuracy of 0.33 mm. These studies demonstrate functional capability of autonomous magnetic continuum devices, encouraging their future adoption in clinical settings.
Associated Publications
Rights
Copyright of the original work is retained by the author.