Design, Control, and Evaluation of a Novel Soft Everting Robot for Colonoscopy

Abstract

Colonoscopy is a medical procedure used to examine the inside of the colon for abnormalities, such as polyps or cancer. Traditionally, this is done by manually inserting a long, flexible tube called a colonoscope into the colon. However, this method can cause pain, discomfort, and even the risk of perforation. To address these shortcomings, advancements in technology are needed to develop safer, more intelligent colonoscopes. This paper presents the design, control and evaluation of a self-growing soft robotic colonoscope, leveraging the evertion principle. The device features a tube with an 18 mm diameter, constructed from stretchable fabric, which grows 1.6 m at the tip under pressurization. A pneumatically driven, elastomer-based manipulator enables omni-directional steering over <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$180^\circ$</tex-math></inline-formula> at the tip. An airtight base houses motors and spools that control the material and regulate growth speed. The robot operates in two modes: teleoperation via joysticks and autonomous navigation using sensor inputs, such as a tip-mounted camera. Thorough <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in-vitro</i> experiments are conducted to assess the system's functionality and performance. Results illustrate that the robot can achieve locomotion in confined spaces such as a colon phantom, while exerting contact forces averaging less than 0.3 N. Our soft robot shows potential for improving the safety and autonomy of colonoscopies, while reducing discomfort to patients.