Under-The-Table Magnetic Actuation System

Abstract

Miniature robots on the millimeter scale and smaller offer novel solutions to challenging problems in healthcare. These remotely actuated robots are able to access constrained spaces to achieve tasks such as drug delivery, sampling, or tissue biopsy. However, clinical adoption of these robots is rare as these systems are often difficult to scale up. One such issue arises from the actuation systems used to remotely control magnetic microrobots, which tend to be bulky and obstruct the surgeons' workspaces. They also do not guarantee wide ranges of magnetic fields and forces in a large patient-sized workspace. In this thesis, we present the design of a permanent magnet-based actuation system that fits within a small cubic region under an operating table. To optimize the design of our system, we also present a new set function maximization approach for efficiently designing E-optimal magnet arrangements with off-the-shelf convex solvers. Our optimization method is evaluated against other approaches and with synthetic data. A proof-of-concept of the system that can achieve fields up to 20 mT is simulated to navigate a magnet through a maze and the bronchial tree of the lungs. We also detail the fabrication process of a small-scale prototype which is built and evaluated for its performance. We also develop a set of control software using ROS2 to actuate our system to produce the desired forces and fields based on user input and autonomous control. Lastly, experiments such as steering a catheter, actuating a capsule endoscope, and autonomously navigating a magnet through maze were conducted.