Designing a Magnetic Endoscope for In Vivo Contact-Based Tissue Scanning Using Developable Roller

Magnetic manipulation has been adopted as a method of actuation in both wireless capsule endoscopy and soft-tethered endoscopy, with the goal of improving gastrointestinal procedures. However, by nature of magnetic manipulation, these endoscopes are typically limited to a maximum of five degrees of freedom (DoF). With the need to introduce additional contact-based sensing modalities for subsurface investigation into these systems as well as to improve overall dexterity, it is both practically and clinically beneficial to recover the lost DoF i.e. the roll around the main axis. This paper presents a method of achieving the magnetic manipulation of an underactuated device by leveraging developable surfaces, specifically, the oloid shape. The design of a clinically relevant magnetic endoscope with all its ancillary elements, as well as contact sensors, is proposed and demonstrated in vivo. The contact sensor data from the in vivo experiments show that for sweeping motions over 100° of roll, contact between the endoscope’s sensor region and the colon wall can be maintained for 74% of the motion.