Toward Autonomous Robotic Colonoscopy: Motion Strategies for Magnetic Capsule Navigation

In this paper, a set of techniques aimed at autonomously navigating a tethered magnetic capsule for endoluminal inspection of the large bowel is presented. The manual navigation of magnetic capsules for colonoscopy can exhibit several challenges if the full control of the capsule pose is left to the clinician. Tight bends, tissue folds and large diverticula can obstruct the motion of the capsule, yielding the control system to apply greater forces and torques, with no substantial effect. For this reason, a supervisory system, capable of influencing the capsule motion to avoid obstruction and to overcome obstacles is here described. The adopted approach is based on the "surfing" principle, where the capsule is navigated in such a way to slide on the tissue folds rather than against them. The proposed technique has been validated by means of experiments in a colon phantom, experiments have shown that the adoption of this approach allows the navigation of 350mm in the phantom, while a fully-manual teleoperation of the capsule only reaches a depth of 75mm.