Electromagnetic actuation system for locomotive intravascular therapeutic microrobot

In this paper, we proposed an intravascular therapeutic microrobot using an electromagnetic actuation (EMA) system with bi-plane X-ray imaging device. The proposed EMA system consists of Helmholtz-Maxwell coils, uniform-gradient saddle coils. The Helmholtz-Maxwell coils are located along y-axis, and uniform-gradient saddle coils are located perpendicular to y-axis. In order to align the microrobot along a desired angle in 2D (dimensional) plane, it is necessary to control of the currents on Helmholtz coil and uniform saddle coil. For a forward and backward direction movement of the microrobot, we precisely control the currents of Maxwell coil and gradient saddle coil. Because the saddle coils can be rotated around the y-axis, the effective actuation plane of the microrobot can be also rotated, and the microrobot can move in 3D space. In addition, for the position recognition of the microrobot in a blood vessel, we adopted a bi-plane X-ray fluoroscopy. If the saddle coils are rotated around the y-axis, an open area is changed. Therefore, the saddle coils and bi-plane X-ray fluoroscopy must be rotated simultaneously. To confirm the feasibility of 3D locomotion of the microrobot, we executed a locomotion test of the microrobot in the blood vessel phantom, where the blood vessel phantom was fabricated by the rendering data from computed tomography (CT) images of the iliac artery and 3D printer.