Nonlinear Magnetic Field Modeling for Electromagnetic Actuation of Miniaturized Medical Robots

One of the major challenges in non-contact actuation of miniaturized medical robots (MMRs) during minimally invasive surgery is precise magnetic force control to ensure accurate movement of these devices inside the human body. This study presents a novel model for the control of the magnetic field generated by a magnetic actuator composed of an electromagnetic coil with a ferromagnetic core. A hybrid model that incorporates analytical formulations of physical phenomena and adapts them based on experimental measurements is used as an alternative approach. This model enables calculation of the in-workspace magnetic field, even in nonlinear conditions associated with high currents in the actuator, offering a significant extension of the operating region. We have experimentally evaluated this model in terms of accuracy, computation time and implementability. The results show that it can be computed accurately in a few milliseconds, making it an ideal choice for controlling magnetic mini-robots.