Development of a biologically inspired locomotion system for a capsule endoscope

Background: A capsule endoscope has a limited ability to obtain images of the digestive organs because its movement depends on peristaltic motion. To overcome this problem, capsule endoscopes require a propulsion system. Methods: This paper proposes a propulsion system for a capsule endoscope that mimics the locomotive mechanism of snails and earthworms. The prototype crawler can elongate and contract itself longitudinally and adhere to a wall via suction cups. Results: We investigated the effect of the inclination angle of the propulsion plane, the mucus viscosity between the propulsion plane and the crawler, and the stiffness of the propulsion plane on the locomotion of the prototype crawler. We found that the crawler could move on a rubber sheet and on inclined planes covered with mucus. We discussed advantages and limitations of the prototype crawler compared to the different locomotive systems developed in former studies. Conclusions: We believe that the prototype crawler provides a better understanding of the propulsion mechanism for use in the gastrointestinal tract.