Modeling and Experimental Validation of Anchoring Resistance of the Radial Expanding Capsule Robot in the Intestine

The anchoring performance of the radial expanding capsule robot (RECR) in the intestine is crucial to the accuracy of the examination. However, there is a lack of relevant research at present. In this article, the anchoring resistance model of the radial expanding capsule robot (RECR) in the intestine is established by the theoretical analysis and verified by the experiment. Based on the anchoring resistance model, the optimization method to improve the anchoring performance of the RECR is proposed. Firstly, the biomechanical properties of the intestine in the expanding state are studied, and the longitudinal contour equation of the intestine is obtained. The anchoring resistance model of the RECR in the intestine is established by analyzing the mechanical characteristics between the capsule robot and the intestine. Then, an experimental platform is built, and the anchoring resistance of the testing dummy imitating the RECR with different radii and lengths in the intestine is tested by the platform. The experimental results verify the correctness of the anchoring resistance model. Finally, the expanding force model of a developed inchworm-like RECR is established by the kinematics and mechanical analysis. And combined with the anchoring resistance model, the anchoring performance of the inchworm-like RECR in the intestine is analyzed. The influence of the RECR design parameters on anchoring resistance is quantitatively analyzed, which provides the theoretical basis for the design and optimization of the RECR.