A Voltage Minimization Control Method for Magnetic Navigation Systems to Enhance the Rotating Magnetic Field

Magnetic helical robots (MHRs) can be actuated by a rotating magnetic field (RMF) and can tunnel through a clogged blood vessel using their rotational motion. We propose a method minimizing the voltage required for each coil to generate the RMF for a magnetic navigation system (MNS). The proposed method maximizes the RMF under the rated voltage of the MNS. In addition, to suppress the increase in impedance during high-speed rotational motion of the MHR, the proposed method utilizes the resonance to which the minimax optimization method is applied. The voltage needed to generate the RMF was analytically derived, with the goal of a fast optimization process in mind, so that the MHR could be controlled in real-time. The proposed method was experimentally verified by measuring the magnetic flux density. In addition, we demonstrated the enhanced navigating and tunneling performance of the MHR from in vitro experiments. Finally, we validated the navigating and tunneling motion of the MHR in an in vivo experiment within a superficial femoral artery of a pig.