Analytical Magnetic Model towards Compact Design of Magnetically-driven Capsule Robot

This study proposes an innovative compact design of a magnetically-driven capsule robot, which embeds an internal permanent magnet (IPM) with a cut-off cylindrical shape, to increase the effectiveness of the internal space distribution. After identifying the second central moment as the evaluation parameter of the efficient distribution of the capsule robot's internal space, three different IPM configurations were compared. Then, the analytical magnetic forces and torques model of the cut-off cylinder-shaped design has been reported and validated by comparison of the analytical model, developed in MATLAB, with the model developed in COMSOL Multiphysics. The comparative results show that the cut-off cylinder-shaped magnet design guarantees a more efficient distribution of the internal space in all analysed cases, and the total mean error of the cut-off cylinder-shaped analytical magnetic model is less than 10%. In conclusion, the cut-off cylinder-shaped magnet compact design increases the efficiency of the distribution of the capsule internal space and the proposed model guarantees sufficient precision and great flexibility to justify its use.