Automated Electromagnetic Manipulation of Micron-Scale Rotors on Unstructured Surfaces in Low Reynolds Numbers

The utilization of magnetic microrotors in low Reynolds number liquid environments holds great promise for a wide range of biomedical applications, owing to their ability to maneuver with flexibility. However, during the movement of the microrotors on solid unstructured surfaces, the interaction with neighboring walls has the potential to generate unpredictable disruptions in its motion. This study proposes an automated electromagnetic manipulation method for guiding micron-scale surface rotors along planar paths at low Reynolds numbers. To this end, we designed a magnetic field drive system using multistage electromagnets, and a double-helix rotor with micrometer-scale dimensions. Additionally, we developed a kinematic model for the microrotor that closely resembles that of wheeled mobile robots and employed a sliding mode motion controller to ensure high-precision path following. Results obtained from simulation and experimentation confirm the efficacy of our proposed method, demonstrating precise following of planar paths.