Dynamic Modeling of a Magnetic Video Capsule for Enhanced Navigation in the Gastrointestinal Tract

Capsule endoscopy, a procedure wherein a patient swallows a capsule that captures images throughout the gastrointestinal (GI) tract, offers greater patient comfort compared to that of traditional endoscopy. Although preferred by patients, this method faces challenges such as capsule retention requiring surgical removal and suboptimal imaging resulting in false negative diagnoses. This work investigates the feasibility of controlling a magnetic capsule endoscope within the GI-tract by use of a robotically controlled, extracorporeal, rotating permanent magnet. A dynamic model was developed by incorporating both contact forces (friction, damping, and spring forces) and non-contact forces (magnetic forces and torques), which were then used to predict the magnetic capsule's behaviour. The model was then validated via use of frequency response testing in and outside a realistic bowel phantom. Open-loop testing within the bowel phantom further evaluated the system's ability to navigate the GI tract. The results demonstrate that the method is feasible, and repeatable trials could be performed traversing the entire bowel phantom in under 600 s. Furthermore, the validation demonstrated that an accurate theoretical representation of the magnetic capsules behaviour is achievable, enabling precise prediction of the necessary actuation inputs.