Research On Structure Design And Dynamic Characteristics Of Direct Wheel Driven Pipe Inspection Robot

With the wide application of oil,natural gas and other fluid energy,pipeline transportation has become an important part of national production and transportation.Due to the use and location of the pipeline,usually beyond the expectations of the workers,not only in the harsh environment,but also difficult to maintain.Therefore,it is inevitable that a kind of direct wheel drive pipeline detection robot is developed and used for continuous detection and advance protection of pipelines.In view of this special working environment,this paper adopts modular segmented design,and divides the whole structure of the straight wheel drive pipeline inspection robot into inspection unit,driving unit,connection unit and rear inspection unit,and each unit is connected with a steering gear.The drive unit is directly driven by the motor,which has simple structure and stable output.At the same time,the angle control actuator is used to realize the movement conversion between the horizontal ground and the pipe;The supporting mechanism adopts spring telescopic type to increase the adaptability to different pipe shapes;The detection unit is designed by the combination of camera and various sensors to complete the detection quickly and effectively.The dynamic characteristics of the robot are analyzed from two aspects of pipeline and horizontal ground crawling,and the motion parameter equations of the robot are obtained respectively,which verifies the rationality of the multi modular structure design.On the one hand,the motion state of the robot in the pipeline is analyzed and studied.The mathematical model of the limit overturning state of the robot is established.The analysis shows that the larger the maximum lateral overturning angle of the robot is,the more stable the operation is.The driving unit of the robot is designed as three body circumferences distributed.The dynamic characteristics of the robot in the straight pipe are analyzed by using the space coordinate method,and the operation equation of the robot in the straight pipe is deduced to verify the feasibility of its structure.Through the coordinate transformation method,the movement state of the robot in the case of turning is calculated.When the robot is running in the elbow,the wheel always contacts with the pipe wall to provide traction,the speed components of the driving wheel relative to the curvature radius of the elbow are different,and the speed of the outer wheel of the pipe is greater than that of the inner wheel,and the speed and contact force of different driving wheels increase with the increase of the curvature radius.Through the detailed analysis of the state and force of the robot crossing the obstacle,it provides a theoretical basis for the rationality of its structure and the stability of crossing the obstacle.On the other hand,the mechanical model of the robot crawling on the horizontal ground is established.Through the analysis of the mechanical problems involved,it is concluded that the friction parts and shear parts are the main influencing factors,which provides theoretical verification for the robot crawling on the horizontal ground.Finally,through ADAMS simulation and prototype experiment,the crawling performance of the robot on the pipeline and the horizontal ground is studied.It is verified that the prototype basically meets the expected technical indicators.The straight wheel drive pipeline inspection robot designed in this paper provides an important theoretical basis for the subsequent engineering application and development of pipeline robot.