Experiment and simulation of a controllable multi-airbag sealing disc of pipeline inspection gauges (PIGs)

The use of Pipeline Inspection Gauges (PIGs) to clean the pipes and understand the exact location of existing pipes is essential to protect them from damage during operation. In-depth study of the most important component sealing disc is a new method to solve the failure of the current PIG in the working process. This study focuses on redesigning the sealing disc in combination with soft robot drive technology. First, the structure of a new multi-airbag sealing disc is composed of a conventional sealing disc and a plurality of airbags located above it. Then, the multi-airbag sealing disc was successfully fabricated by using 3D printing technology and multi-step molding, and finally the active control of the multi-airbag sealing disc was realized by inflating the airbag. For the newly designed multi-airbag sealing disc, the most important concern is the bending angle β of the sealing disc and the expansion ratio η of the airbag. Numerical and experimental results were compared to verify the accuracy of the numerical method. Based on this method, the effects of the position of the airbag, the height rate, and the thickness rate on the bending angle of the multi-airbag sealing disc and the expansion ratio of the airbag were studied. The results show that at a given air pressure, the position of the airbag does not substantially affect the expansion ratio of the airbag itself, and the smaller the distance between the airbag and the outer edge of the sealing disc, the easier it is to bend the sealing disc. The larger the height rate, the smaller the thickness rate, and the larger the bending angle of the sealing disc, the larger the expansion ratio of the airbag.