Multi-jointed pneumatic sealing disc of fluid-driven pipeline robot: impacts of structural parameters on performance

Pipeline inspection gauge (PIG) is often blocked in the ageing pipelines of stacked objects. A novel pneumatically controlled sealing disc has been designed to address the issue of PIG's blockage. Compared to traditional passive-controlled sealing discs, the new sealing disc incorporates a multi-jointed pneumatic webbed foot that enables active control. It provides both single execution mode and multiple execution mode capabilities, allowing it to achieve partial bending through the inflation of a single foot and thereby enhancing sealing performance during active control. A finite element method (FEM) was introduced and effectively validated by comparing simulation results with experimental results of the inflatable bending experiments of a single foot. Then the performance of the sealing disc with single execution mode and multiple execution mode was compared using the FEM, and the results show that they have good consistency. Next, the effects of four kinds of materials and five structural parameters on the performance of the sealing disc were studied using the FEM. The results show that the multi-material structure has better performance compared to the same materials and the Ecoflex series demonstrates greater responsiveness in inflation experiments. As the air pressure grows, the position parameter of the joint has little effect on the bending angle as well as the expansion ratio, and the bottom disc thickness has also slightly influence on the expansion ratio. Meanwhile, the thicker the webbed foot thickness, the smaller the slope angle and the thinner, the larger the bending angle; the smaller the slope angle, the thicker the webbed foot thickness, the larger the expansion ratio. The conclusions obtained in this paper are beneficial for the design and optimization of PIG sealing discs for actively controlling. The research results provide theoretical reference for the study of intelligent and efficient pipeline pigging technology.