Magnetic Navigation System Utilizing a Closed Magnetic Circuit to Maximize Magnetic Field and a Mapping Method to Precisely Control Magnetic Field in Real Time

We propose a novel closed-circuit magnetic navigation system (CMNS), which utilizes eight electromagnets connected by back yokes to maximize a magnetic field. We first show the effectiveness of a closed magnetic circuit (CMC) and conduct a parametric analysis to design a single CMC, which is utilized to construct the whole CMNS. A magnetic field mapping method is also developed utilizing the finite-element method and polynomial regression to evaluate and control the magnetic field over almost the whole workspace in real time. We investigated how the magnetic field changed based on the shape of core tips by comparing the isotropic magnetic field control authority, which is the ability to generate an equal magnetic field over the workspace regardless of the position and direction of the magnetic field. We experimentally verified the mathematical assumption that the magnetic field generated from the proposed CMNS can be linearly proportional to the applied current and that the magnetic field of the proposed CMNS can be expressed as a superposition of the magnetic fields generated by each electromagnet. Finally, we verified the effectiveness of the developed CMNS by performing experiments related to steering a commercial magnetic catheter.