Research On Running Characteristics Of Pipeline Robot Driven By Fluid Pressure

Pipeline robots driven by fluid pressure can run automatically without external energy supply equipments,which are especially suitable for the dredging and detection in the long-distance transportation pipeline.For the present,the numerical researches on the pipeline robot are mainly concentrated on the one-dimensional or two-dimensional model,and there are few reports about running state of the pipeline robot accounting for fluid-structure interaction(FSI).In the present work,the Couple Euler Lagrange method(CEL)is used to simulate and study the running mechanism of the pipeline robot when running in the pipe based on 3D models.Firstly,in the work,the working principle and structure of pipeline robot are analyzed,and experiment researches are carried on material properties of the cup installed on the robot,and the stress-strain curves are obtained by using the uniaxial tensile test method widely applied in engineering.Combining with the hyper-elastic theories,the Neo-Hookean model,Yeoh model and Mooney-Rivlin model are studied mainly.The material constants and hyper-elastic models of the cup are obtained according the test data and hyper-elastic theories.The structures of the pipeline robots are designed,and then are simplified in an appropriate way.The finite element models of pipeline robots are built.Based on the basic theories of fluid mechanics and fluid-structure interaction,the mechanism of the robot running is studied,and the boundary conditions are set reasonably,and the numerical simulation models are determined.Through the numerical examples,the rationality of the models get verified.The main reasons of causing and maintaining the speed fluctuation of the robot are analyzed,and the mathematical model of velocity fluctuation is established,then the kinematics analysis of the robot when running in the pipe is proposed.Through the numerical examples,the velocity fluctuation curves of the pipeline robot under different working cases are obtained,and the influence laws of main parameters on the speed are obtained.Finally,the main factors impacting the quality of running are proposed,and the relations among the sizes when the robot is running in the pipe are deduced,then the mechanisms of turning are analyzed.Through numerical simulations,the speed,driving force,friction are explored,and the laws of main design parameters of robot how to impact robot running are obtained.This article will provide the basis and reference to the optimization design of the pipeline robot.