Abstract: Robotic capsule endoscopes (RCEs) are being widely investigated to improve the state of various endoscopy procedures. This paper presents the novel design of a multi-DOF sensor-enabled RCE for colonoscopies (Endoculus) and evaluates porcine in vivo and ex vivo performance. The novelty of the design includes a custom “double-worm” drive that removes axial gear forces while reducing radial moments, and the full parameterization of gear geometries allows for size minimization via an optimization routine over design constraints. Two independently controlled motors drive micro-pillared treads above and below the device allowing for 2-DOF skid-steering, even in a collapsed lumen. The Endoculus contains all functionality of a traditional endoscope: a camera, adjustable LEDs, channels for insufflation and irrigation, and a tool port for endoscopy instruments (e.g., forceps, snares, etc.). Additionally, the Endoculus carries an inertial measurement unit, magnetometer, motor encoders, and motor current sensors to aid in future autonomy strategies. Porcine surgical evaluation demonstrated locomotion up to 40 mm/s on the colon mucosa, 2-DOF steering, the ability to traverse haustral folds, and functionality of endoscopy tools. This platform will enable future validation of feedback control, localization, and mapping algorithms in the unconventional in vivo environment.

Formosa, G.A., Prendergast, J.M., Edmundowicz, S.A., Rentschler, M.E., “Novel Optimization-Based Design and Surgical Evaluation of a Treaded Robotic Capsule Colonoscope,” IEEE Transactions on Robotics. 36(2): 545-552, 2020.

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