Electromagnetic Actuation System with Real-Time Magnetic Feedback Control for Miniature Robot Manipulation

In recent years, advances in precise magnetic control have enabled the remote navigation of microrobots with high dexterity in confined spaces, supporting applications such as targeted therapy, thermal ablation, and precise drug delivery in biomedical settings. However, at the scale of the human body, most existing mobile electromagnets systems face significant limitations, including poor magnetic field uniformity and limited control stability. Here, we introduce a mobile electromagnetic actuation system which could achieve real-Time control of 3D magnetic field with high precision and uniformity within a human-scale workspace. The system's workspace is optimized using finite element analysis (FEA) to identify the plane with the highest magnetic field uniformity. Subsequently, the magnetic field of electromagnets array is calibrated based on the 3D interpolation function, and precise magnetic field is achieved through the closed-loop control based on feedback from field vector errors. Finally, experimental validation confirms that the system maintains a magnetic field error below 2%, and is capable of actuating helical millirobot with maximum speed of eight body lengths/s. The system also successfully navigates the robot through a natural cavity model and lung model, confirming its effectiveness in complex, confined spaces. Results obtained from experimentation confirm the high precision of the proposed system, demonstrating its potential for future clinical applications.