A Self-Propelled Inflatable Earthworm-Like Endoscope Actuated by Single Supply Line

Design of a self-propelling endoscope has been of interest for decades, as it allows for simplified medical examination techniques and improved patient comfort, together with advanced analysis capacity. In this paper, we describe the development of a fully automatic, multiple-balloon system achieving peristaltic locomotion, controlled by a single supply channel. The system employs the nonlinear pressure-radius characteristics of elastic balloons to simultaneously control numerous balloons with a constant inlet pressure. The balloons are connected in series and the flow is controlled by small orifices, which delay the flow between them. The proposed multiple-balloon system requires no moving parts, no electronics, and relies on dynamics of the fluid flow between serially interconnected inflatable balloons. The entire system is made of disposable silicone and is plastic-modeled by injection molding. Additionally, the cost of such a system is expected to be low and suitable for numerous biomedical applications as it can be easily scaled down due to the need for only one supply line. Mathematical modeling, and simulation and experimental results of a system prototype are presented in this paper. Experimental results in the straight cylinder show close correlation to simulated system.