Tether-colon interaction model and tribological characterization for front-wheel driven colonoscopic devices

ABSTRACT Front-wheel driven colonoscopic devices are being researched to provide a less invasive alternative to conventional colonoscopy. Such devices are required to pull a soft-tether along the colonic tract in order to screen it. To date, the resistance force introduced by the tether during locomotion has not been modeled nor experimentally quantified. In this paper, we present an analytical model that characterizes the colon-tether interaction when pulled along the colon lumen. The theoretical model is experimentally validated in ex vivo conditions: tests quantified the required pulling forces for a set of colon paths and soft-tether materials. The validated model concluded that the resistance force exponentially grows as a function of the product of contact angle and coefficient of friction.