Design, dynamics and implementation of a novel modular pipeline inspection robot based on active flexible joints

The pipeline inspection robot can move freely through complex, variable, and unstructured pipeline environments, playing a crucial role in the field of health management and maintenance of pipeline systems. This paper proposes a novel modular pipeline inspection robot for industrial applications based on active flexible joints, called RoboChain-II. The flexible variable structure and adaptive functions of the robotic system enable it to accommodate a wide range of pipe sizes and configurations. The combination of the belt drive structure and tension sensing module can actively regulate the angle between monomers and adapt to changes of pipe diameter. The unique design of the opposed Mecanum wheel movement mechanism can achieve the forward-rotation coupling motion of the entire system. The high robustness of the robot structure and operation is ensured by its scalable modularity. A series of extensive experiments were conducted in pipes of varying diameters and configurations, demonstrating the robot’s capability to adjust inter-module angles, execute three-dimensional movement in vertical pipelines, and navigate bends and inclines. The adaptive variable structure of the joint enables the robot to respond rapidly, completing adjustments to different pipes within just 4 s. Moreover, it can complete a full rotation around the central axis of the pipe within 40 s, allowing it to bypass inaccessible areas or obstacles. The results demonstrate that RoboChain-II, equipped with active control of flexible joints, can precisely adjust inter-module angles to perform various tasks. The modular design also provides the robot with exceptional flexibility, enabling it to adapt to a broader range of oil and gas pipeline inspection scenarios.