Prototype Design and Testing of a Self-Propelled Vibro-Impact Capsule System for Lower Gastrointestinal Endoscopies

Abstract

Bowel cancer is a steadily-growing killer every year which now has been ranked second worldwide for cancer death. To mediate such implications on human health risk, various measures can be taken whether from the source -- guide people to establish healthy and active lifestyle, constant surveillance of any potential signs of bowel cancer and inhibiting it from the start, or from the end -- thorough diagnosis and treatment towards the occurred bowel cancer in an efficient way. This work explored the possibility of a cost-effective and efficient solution towards surveillance of the gastrointestinal diseases on the potential patients, which aims to acquire a higher accept rate from the patients than the traditional endoscopic procedures. Efforts have been devoted through the last two decades already, as a series of actively-controlled capsule robots and catheter heads developed by researchers and robotics engineers. After evaluating the existing designs, an evolution is clearly seen with a transfer from pure mechanical crawling strategy to adoption of on-board powering system, and now to a wireless remote magnetic control solution. I have chosen the magnet-guided solution and while this sounds to be a cliché, a combination of vibro-impact dynamics into the system for self-propulsion is the novel part of my design. I proposed a propulsion method which can effectively overcome the complexity of intestinal morphology. This technique is able to let the gastroenterologist maneuver and steer the robot inside the patient's body, to conduct a real-time diagnosis. With the examination time reduced from eight hours to less than an hour for diagnosing the entire gastrointestinal system, the burden on patients and gastroenterologists can be greatly mitigated. In this work, a total of three capsule designs were proposed, and before the capsules, a vibrational versatile prototype was proposed to demonstrate the concept of the vibro-impact self-propulsion. The findings of this work show that the vibro-impact magnetic control method can be used to navigate the capsule through a colon phantom with an averaged progression speed of up to 20 mm/s travel speed in ex vivo test with rigid environment, and 40 mm/s with soft environment. This work also provides the dynamic analysis of the proposed vibro-impact mechanism by using a new mathematical model which can serve as a solid reference in the wider research field of magnetically-actuated capsule robots.