Motion Primitives for Low Contact Force Magnetically-Driven Navigation of Endoscopic Capsules

Magnetically-driven robotic capsules have the potential to become the gold standard for colonoscopy, reducing patient pain while simplifying the overall procedure execution. The usage of a robotic arm to maneuver a permanent external magnet (EPM) for controlling the motion of a magnetic capsule within the gastrointestinal (GI) tract has been successfully demonstrated in pre-clinical scenarios. However, current control strategies struggle to navigate the capsule under realistic scenarios. In this work, the authors deduce a set of motion primitives for the EPM that optimize the navigation force provided to the capsule by reducing the contact force. Such motion primitives consider, for the first time, the resistance force introduced due to the contact between the endoscopic capsule and the GI tract. The results show that the proposed motion primitives enable the capsule to manage realistic scenarios, such as a 30 mm soft obstacle mimicking the compression of an organ, while a 10 mm obstacle would impede state-of-the-art strategies. In summary, the proposed control strategy improves the magnetically-driven endoscopic capsule navigation by optimizing the locomotion force and reducing by ~81% the contact force applied to the GI wall with a consequent reduction of the endoluminal stress.