Dynamic behaviour of an in-pipe sensor-based platform for soil water monitoring

- Sensor-based technologies for pipeline soil water monitoring.
- Kinematics equations for the robotic platform were derived.
- Experimental vibration analysis for structural identification of an in-pipe platform.

In this study, the dynamic behaviour of a sensor-based platform that travels through an underground pipeline network is investigated. The platform consists of a soil water sensor, placed on two articulated wheeled bases. In order to improve the maneuverability of the platform within the curved sections of the pipeline, an extension rod between one of the wheeled bases and the soil water sensor was added. Firstly, the behaviour of the platform in a curved section is demonstrated using mathematical modeling and numerical simulation. According to simulation results, the extension rod improves the turning radius (Rc = 0.26 m) of the platform significantly. On the other hand, it reduces the clearance (g = 0.002 m) between the soil water sensor and the inner sidewall of the curved pipe, affecting at the same time the tractive forces. Next, the vibration effect of the electromechanical devices on the sensor-based platform at low and high speed operation is investigated. The vibration magnitude for the case of high speed operation is almost identical to that for low speed operation, because it is mainly determined by the amplitude of the strongest mode. The platform modal behaviour depends only on the constructional details and is irrelevant to speed and type of excitation.