Design and Comparison of External Permanent Magnet Topologies for Improving Motion Control in Gastrointestinal Examination

The Capsule endoscope (CE) is widely used for intestinal examinations due to its non-invasive advantages. The external permanent magnet (EPM) is used as the motion control device of the CE, and the magnitude and distribution of the magnetic field strength and gradient generated by them affect the motion performance of the CE. To improve the motion performance of the CE in the intestinal tract, this study compares the relationship between the electromagnetic force and torque produced by the EPMs of spherical, cylindrical, and square structures on the internal permanent magnet (IPM) at different rotational angles and positions according to the driving strategy of the CE under the same conditions of the magnet volume by means of finite element simulation software. The results show that the cylindrical EPM can contribute best to the CE. Therefore, the EPM with a larger surface area and perimeter structure can provide a better contribution to the driving force of the CE under the same magnetization intensity.