Magnetic Navigation System Composed of Dual Permanent Magnets for Accurate Position and Posture Control of a Capsule Endoscope

We developed a magnetic navigation system (MNS) composed of a magnetic field control part and a robot arm part to precisely control the position and posture of a capsule endoscope (CE). The magnetic field control part generates a magnetic field by controlling the magnetization directions of dual permanent magnets (PMs) using motors, and the robot arm part supports and freely moves the magnetic field control part in three dimensions. First, we calculated the magnetic field generated by the dual PMs of the MNS by utilizing point-dipole approximation, and the magnetic force between the PMs of the MNS and the CE. We set up an optimal design problem to determine the rotational angles of the magnetization direction of the dual PMs of the MNS to align the CE to the given direction. We validated the proposed optimal design problem by utilizing finite element analysis. By using the developed MNS and a commercial CE, we measured the magnetic force acting on the CE and compared it with the simulated results of the finite element analysis. Finally, we performed a gastric endoscopy in a mimetic stomach and confirmed that the proposed MNS can effectively examine the major parts of a stomach.