RectMag3D: A magnetic actuation system for steering milli/microrobots based on rectangular electromagnetic coils

Milli/microrobots benefit from their small size and can perform minimally invasive surgery in a limited tissue space and eliminate the need for fine operations such as thrombus, which not only reduces trauma to patients but also shortens the recovery period after surgery. In order to realize motion control of the milli/microrobot at a small scale, the external magnetic field-based control method has a significant advantage of wireless connection, safety, and high efficiency compared to other external actuation ways. Aiming at the actuation of milli/microrobots in human tissue fluid during a medical operation, we designed a milli/microrobot magnetic actuation system called RectMag3D, which is based on rectangular electromagnetic coils. It can realize five-degree-of-freedom motion control of milli/microrobot in three-dimensional space. It has the advantage of the accurate modeling of a magnetic field from each rectangular coil. Therefore, accurate control can be achieved. In this paper, the design and modeling of the proposed system have been introduced. A linear programming algorithm has been applied to achieve fixed-point actuation and displacement actuation. Experiments show that the milli/microrobot can realize the steering and linear motion to the target point in any direction in the limited working space under the control of the magnetic actuation system.