  Colonoscopy is considered the golden standard for cancer screening of the
lower gastrointestinal (GI) tract, with screening programs all over the world
considering lowering the recommended screening age. Nonetheless, conventional
colonoscopy can cause discomfort to patients due to the forces occurring
between colonoscopes and the walls of the colon. Robotic solutions have been
proposed to reduce discomfort, and improve accessibility and image quality.
Aiming at addressing the limitations of traditional and robotic colonoscopy, in
this paper, we present the SoftSCREEN System, a novel Soft Shapeshifting
Capsule Robot for Endoscopy based on Eversion Navigation. A plurality of tracks
surrounds the body of the system. These tracks are driven by a single motor
paired with a worm gear and evert from the internal rigid chassis, enabling
fullbody track-based navigation. Two inflatable toroidal chambers enclosing
this rigid chassis and passing through the tracks, cause them to displace when
inflated. This displacement can be used to regulate the contact with the
surrounding wall, thus enabling traction control and adjustment of the overall
system diameter to match the local lumen size. The design of the first tethered
prototype at 2:1 scale of the SoftSCREEN system is presented in this work. The
experimental results show efficient navigation capabilities for different lumen
diameters and curvatures, paving the way for a novel robot capable of robust
navigation and reliable control of the imaging, with potential for applications
beyond colonoscopy, including gastroscopy and capsule endoscopy.
