The Modelling, Analysis, and Experimental Validation of a Novel Micro-Robot for Diagnosis of Intestinal Diseases

Intestinal-related diseases all around the world are increasing nowadays, and gradually become stubborn diseases threatening human health, and even lives. Diagnosis methods have attracted more and more attention. This article concerns a non-invasive way, a novel micro-robot, to diagnose intestinal diseases. This proposed micro-robot is a swallowable device, 14 mm in diameter, like a capsule. In order to make it possible for the micro-robot to move forward, backward, or anchor itself at a suspicious lesion point in the intestine with different lumen diameter sections, two key mechanisms have been proposed. One is an expanding mechanism with two-layer folded legs for anchoring. The designed expanding mechanism could realize a large variable diameter ratio, upwards of 3.43. In addition, a pair of specific annular gears instead of a traditional pinion drive is devised not only saving limited space, but also reducing energy loss. The other mechanism is a telescoping mechanism, possessing a self-locking lead screw nut system, which is used to obtain axial motion of the micro-robot. Then, the kinematics and dynamics of the micro-robot are analyzed. After that, the following experiments, including force tests and locomotion tests, are constructed. A good match is found between the theoretical results and the experimental data. Finally, in vitro experiments are performed with a prototype to verify the safety and reliability of the proposed micro-robot in porcine intestine.