Motion Control of Magnetic-Controlled Spiral Microrobots for In-vitro Plaque Removal

Non-contact magnetic-controlled microrobots exhibit great potential in vascular intervention medicine due to their efficiency and safety. This paper introduces a novel helical magnetic microrobot designed and manufactured with integrated consideration for structural functionality and controllability. The microrobot is capable of autonomous rotational motion and effective grinding removal of simulated arterial plaque in-vitro. A magnetic control system employing three sets of orthogonally placed Helmholtz coils is presented, providing a uniform rotating magnetic field. To validate the proposed design, in-vitro experiments including linear velocity measurement, path control, and semi-occluded plaque grinding are conducted. An efficient closed-loop control strategy is proposed for semi-occluded plaque removal, allowing real-time adjustments of grinding mode, intensity, moving direction, and speed based on image feedback of the microrobot's position and plaque conditions, thus achieving efficient and precise plaque removal. Experimental data indicate that the microrobot can achieve a maximum travel speed of 15 mm/s and a semi-occluded plaque removal efficiency of 0.75 mm/min, demonstrating promising results in potential arterial plaque removal in vivo.