Analytical Magnetic Model Towards Compact Design of Magnetically-Driven Capsule Robots

This work proposes a magnetic model for interaction forces and torques calculation between two permanent magnets applied in external magnetically-driven capsule endoscopies. The internal permanent magnet (IPM) embedded in the robotic capsule is characterized as a truncated cylinder which is beneficial to increase the efficiency of the internal space distribution of the capsule, especially for an active capsule robot integrated with medical functions like imaging, standard medical tool insertion, etc. In this paper, the second central moment is used first as the evaluation parameter to choose the shape of the IPM, i.e., the truncated cylinder, considering the demanding efficiency of the internal space of a capsule. Then, the analytical magnetic forces and torques model for the truncated cylinder-shaped permanent magnet has been reported and validated by comparison of results from the proposed magnetic model developed in MATLAB and the software of COMSOL Multiphysics. The experiments are presented in the end to demonstrate that the compact design of the capsule robot with a truncated cylinder-shaped IPM can work effectively and efficiently.