Structure Design And Motion Control Of Pipeline Robot

In recent decades,with the progress of science and technology,the development of industry and the improvement of economic level,great achievements have been made in the construction of pipeline transportation in China.Compared with automobile,train and other transportation modes,pipeline transportation has many advantages,such as economy,safety,and its application is more and more extensive.Long-term use of oil and gas pipelines will cause corrosion,perforation or rupture,which will lead to oil and gas leakage,thereby affecting the surrounding environment,and even fire,explosion and other serious consequences.Manual pipeline maintenance is time-consuming,laborious and costly,which requires pipeline robots to regularly repair and maintain pipelines.Most of the existing pipeline robots in the market have poor obstacle-crossing ability,can not adapt to pipelines with different diameters and large slopes,and their passage capacity are poor in complex pipelines such as elbows.In order to solve the above problems,this paper presents a general design scheme of a wireless cable-type pipeline robot with self-variable diameter and 120 degree uniform distribution of three caterpillar feet.The robot has the advantages of flexible walking,simple control and large traction force.The main contents of this paper are as follows:(1)Combining the advantages and disadvantages of the existing pipeline robot,the requirements and performance indicators of the project design,the overall design scheme of the cable-less tracked pipeline robot with differential function and variable diameter function is put forward,and the mobile mechanism and variable diameter mechanism of the pipeline robot are selected and designed.The three-dimensional model of pipeline robot is designed with SolidWorks software.(2)The model of working attitude angle and closing force of tracked pipeline robot is established,and the influence of working attitude angle on closing force is analyzed.The attitude angle of tracked pipeline robot when closing force is maximum is the expected stable working state.The model of spring preloading force is established to obtain the minimum spring preloading force that pipeline robot can work stably.The walking model of pipeline robot in horizontal straight pipe is constructed and determine its dynamic equation.The motion mechanics equation of a group of supporting rods of the variable diameter mechanism are analyzed,which provide the theoretical basis for the dynamic simulation analysis of the variable diameter mechanism in Chapter 4.(3)Using ADAMS software,a virtual prototype of pipeline robot is constructed and a simulation environment is established to conduct the crawling pass-through experiment of horizontal straight pipeline,variable diameter pipeline and bend pipe with large radius of curvature.The parameterized model of a group of supporting rods of variable diameter mechanism is constructed and simulated.(4)The overall control structure of the pipeline robot system is built,including the design of hardware framework and the design of software implementation process.Hardware design includes selection design of microcontroller ARM,sensor,motor driver,etc.Software design is mainly the process design of action realization.(5)The pipeline robot test platform is built,including the physical prototype assembly and the assembly of the simulated pipeline environment.The crawling experiments of pipeline robot in horizontal straight pipe,variable diameter pipe,large slope and vertical pipe were carried out.