Modeling and Experimental Validation of the Locomotion of Endoscopic Robots in the Colon

In this paper we present a biomechanical study to evaluate the efficiency of the motion of endoscopic robots in the colon, with a special focus on “inchworm” locomotion. A quasi-linear viscoelastic model for soft tissues has been introduced in order to find the mechanical behavior of colon and mesenteries. A study of efficiency of the motion phases, through biomechanical and geometrical factors, allowed us to calculate the “critical stroke” to perform motion inside intestinal walls. This study has provided the guidelines to design a high-stroke pneumatic robotic prototype for colonoscopy. Phantom and in vivo tests have been extensively performed and have shown high efficiency of the robot in navigating inside a pig’s intestine; the performance of the semi-autonomous robot has achieved that of traditional colonoscopes in terms of traveled colon length. KEY WORDS—robotic colonoscopy, inchworm locomotion, intestinal soft tissues, viscoelasticity, fluoroscopy