Frictional resistance model for a capsule and an intestine with different central axes based on the intestinal nonlinear constitutive relationship

Abstract

A magnetically controlled capsule endoscopy has a broad application for the detection of gastrointestinal diseases. The frictional resistance between a capsule and an intestine will affect the position control of the capsule. A quasi-linear viscoelastic (QLV) model is developed to describe the biomechanics of small intestines of a rabbit under the finite deformation. When the capsule is moving inside the intestine whose centerline is deviated from that of the capsule, a frictional resistance prediction model is created based on the established intestinal constitutive relationship, and the model is further validated by the frictional resistance experiment for the capsules with different diameters in small intestines of a rabbit. The work can help to design and optimize the magnetically controlled capsule endoscope.