Dynamics of a vibro-impact capsule robot self-propelling in the small intestine with multiple circular folds

Abstract Despite advancements in capsule endoscopy, existing models lack controllable motion, limiting their effectiveness in navigating complex folds and the variable stiffness of intestinal tissue. To address this gap, this study investigates the motion of a self-propelled capsule robot designed to overcome the limitations of current endoscopic technology by actively navigating the small intestine, particularly considering the influence of multiple circular folds. In this research, we employed the dynamic model developed by Yan et al. (Eur. J. Mech. A-Solid, 105:105233, 2024). The model was validated using two-dimensional finite element modelling and an experimental setup with an artificial gut model, showing high consistency with theoretical predictions. Our analysis focuses on key parameters, such as fold height, fold thickness, and tissue stiffness, finding that higher and thinner folds on harder tissues present greater resistance. This increased resistance necessitates the application of greater force by the capsule for effective navigation. These findings suggest that while self-propelled capsule robot can achieve consistent motion under various conditions, its movement may become irregular in complex physiological environments. This underscores the need for optimising advanced control strategies to enhance their performance. By improving navigation through the small intestine, this technology has the potential to enhance the accuracy and reliability of gastrointestinal diagnoses, leading to better clinical outcomes and advancements in non-invasive diagnostic techniques.