Colonoscopy is widely considered the gold standard for inspection of the colon. The procedure is however not without issue, current colonoscopes have seen little change or innovation throughout their 40 years of use with patient discomfort still limiting success. The aim of this PhD study was to develop a locomotion system for use on a robotic device that can traverse a liquid filled colon for atraumatic inspection and biopsy tasks. The PhD was undertaken as part of a larger two-centre EU project, which aimed to bring about a change in the way colonoscopy is done by moving to “robotic hydro-colonoscopy”.
In this thesis the initial development and testing of an amphibious locomotion concept for use in a procedure known as hydro-colonoscopy is described. The locomotion system is comprised of four Archimedes’ screws arranged in two counter-rotating pairs. These aim to provide propulsion through a fluid-filled colon as well as provide locomotive traction against colonic tissue in partially fluid-filled or collapsed sections of the colon, such as the splenic flexure.
Experimental studies were carried out on a single screw system in fluid and dual counter-rotating screws in contact conditions. These show the system’s ability to generate thrust in the two discrete modes of locomotion of the amphibious system.
A 2:1 scale prototype of the proposed device was produced and features compliant screw threads to provide atraumatic locomotion. The scale prototype device was tested in ex-vivo porcine colon. The developed system was able to traverse through lumen to limited success, which demonstrated that this concept has the potential for use on an intra-luminal robotic device
The key contributions of this research are: variable geometry locomotion system; amphibious locomotion using Archimedes’ screws; experimental assessment of the locomotion in fluid, contact and amphibious states; and analysis of the contact dynamics against tissue
