Optimising the locomotion of a vibro-impact capsule robot self-propelling in the small intestine

Abstract

Circular fold is one of the biggest barriers for resisting endoscopic robots moving in the small intestine. Overcoming such a resistance force for progression during endoscopic procedure may significantly improve diagnostic efficiency. This paper studies the locomotion of a vibro-impact capsule robot self-propelled on a small intestine substrate when encounters various types of circular folds. A new capsule-fold model is developed to understand capsule-fold interaction and determine the optimum control parameters (the frequency and amplitude of excitation) for a successful crossing motion. Extensive bifurcation analyses show that the geometry and mechanical properties of the circular folds do not have a significant influence on capsule's bifurcation patterns but affect its progression in terms of fold crossing. To this end, numerical studies using path-following techniques implemented via the software COCO are performed. In this way, parameter-dependent families of periodic solutions of the capsule-fold model are studied, and critical points are detected to allow to develop control strategies for the capsule motion, in particular in order to cross certain types of circular folds by suitably varying its control parameters.