Design Of Autonomous Underwater Pipeline Inspection Vehicle

Pipeline transportation is widely used because of its advantages of economy and safety.Long-term use of underwater pipeline will appear corrosion,cracks and other situations,serious cases will occur safety risks.Manual inspection of pipelines is time-consuming,laborious,costly and difficult to ensure personal safety.Therefore,it is necessary to use underwater vehicle to inspect the pipeline regularly.In our study,a frame-type autonomous underwater pipeline inspection vehicle was designed,which can independently detect pipelines in offshore waters,lakes and other shallow water environments.A single inspection can detect pipelines for a whole week and improve the detection efficiency.The main research contents are as follows:1.According to the autonomous underwater pipeline inspection vehicle working environment,functional requirements and performance indicators,we put forward an overall design scheme for a frame-type autonomous underwater vehicle with dual mechanical rocker arms.In this overall design of autonomous underwater vehicle,we completed the framework design,structure design,watertight compartments propeller layout,the mechanical arm design and the control scheme design and we also set up three-dimensional model.2.In order to reduce power loss and improve endurance,we optimized the structure of autonomous underwater pipeline inspection vehicle.ANSYS Workbench optimization module was used to optimize the parameters of the cylindrical cabin in the sealed chamber,and the sensitivity of the outer radius of the cylindrical cabin,the width of the stiffeners and the thickness of the stiffeners to the cylindrical cabin mass was studied.The final parameters that meet the conditions and can effectively reduce the mass were analyzed,and the strength and stiffness of the optimized cabin were checked.Fluent software was used to calculate the resistance of the vehicle under the overall forward working condition,and the frame structure was optimized according to the pressure cloud image.Compare the resistance before and after optimization.3.In order to verify that the designed and optimized structure meets the requirements of underwater operation of the vehicle,finite element analysis was carried out on the main structure.The GASKET element in ABAQUS was used to simulate the nonlinear behavior of GASKET compression,and the GASKET sealing structure of GASKET was analyzed.Mooney-Rivlin constitutive model was used to simulate the large deformation behavior of Oring,and the sealing structure of O-ring was analyzed.Compared with the maximum working water pressure,the contact pressure between gasket and O-ring and cabin body was analyzed to evaluate its tightness.The finite element analysis of the frame structure is carried out to analyze the strength and stiffness of the frame structure under lifting and standing conditions.4.We built and detected the physical prototype of autonomous underwater pipeline inspection vehicle.Thruster thrust test and sealing chamber test to test the actual thrust of the selected propeller and sealing chamber.The kinematic experiments included advance and retreat,submersion and tracking experiments to verify the vehicle’s smooth sailing ability along the pipeline.The experiment of pipeline crack target detection included model training and detection results,which verified the vehicle’s ability of underwater target detection.