Study of Frictional Properties of the Small Intestine for Design of Active Capsule Endoscope

The necessity of a self-actuation mechanism for the capsule endoscope makes it important to gain an understanding of the frictional force, which will be encountered by the capsule when it is guided through the gastrointestinal tract. We have carried out in-vitro experiments in the porcine small intestine to investigate the effect of the capsule dimension and moving speed on the friction using fifteen specially designed prototypes. Friction of 20~80 mN was recorded for the capsules with diameters of 8~13 mm and moving at a speed of 0.5 mm/s. We also measured the friction under different speed, and found that the friction increased accordingly with the speed. The intrinsic cause of the friction of the small intestine is discussed based on the analysis of the experimental data. It is believed that the viscoelastic properties of the tissue play an important role in the frictional characteristics of the small intestine