Research On Position Control And Error Compensation Of Pipeline Positioning Manipulator In Crude Oil Environment

The crude oil heat exchanger has more than 800 pipelines.The pipeline positioning manipulator is installed in the shell of the heat exchanger,which is responsible for the positioning and cleaning of all pipelines one by one while the heat exchanger works normally.The heat exchanger is filled with crude oil with high temperature,high pressure and high viscosity.If the positioning is not correct,the cleaning head at the end of the manipulator will collide with the tube disc when it extends out,which will cause very serious consequences.Therefore,it is an urgent problem to be solved which way of cleaning and precise positioning.Aiming at this goal,this paper will determine the cleaning sequence of the pipeline traversing the heat exchanger according to the pipeline layout plan;then design the controller and position feedback system to determine the overall plan of the control system;design the test-bed for the debugging of the control system;finally,analyze the error sources of the system and complete the error compensation to make the positioning of the system more accurate.The main contents of this paper are as follows:Firstly,the scheme of cleaning the heat exchanger pipeline by pipeline positioning manipulator is designed.According to the requirements of cleaning all pipelines,the improved genetic algorithm is used to design the cleaning sequence of all 800 pipelines.The effectiveness of the improved genetic algorithm is determined through simulation experiments,and the optimal cleaning sequence is obtained.Then,the S-curve is used to deduce the trajectory planning between adjacent pipelines,and the trajectory planning is optimized the kinematics model of pipeline positioning manipulator is established,and the formula of forward and inverse kinematics is proved to be correct by using the robotics toolbox module.The determination of pipeline cleaning scheme lays a foundation for the design of control system.Secondly,the position control system of the manipulator is designed.The controller model of the position control system is established,three typical PID control algorithms are simulated by Simulink,and the optimal control method is obtained.In order to locate accurately,the position feedback system is constructed by using three-way wire sensor,and the position coordinates of the end of the pipe positioning manipulator are deduced.Finally,the general scheme of position control system is built by PC + PLC.Finally,the test-bed is designed and the system error is analyzed and compensated.In order to facilitate the debugging of the positioning control system,a test-bed scheme for the debugging of the control system is designed.After defining the function and structure requirements of the test-bed,the mechanical structure,driving system,material selection and other contents of the positioning manipulator are designed,and the key parts of the positioning manipulator are simulated and analyzed based on ANSYS software,which verifies the feasibility of the positioning manipulator.In order to ensure the accurate positioning of the manipulator,the error sources of all aspects of the system are analyzed.The position and posture errors of the end of the positioning manipulator are derived by differential method.The end positioning errors are allocated to two rotary joints for error compensation to eliminate the positioning errors of the system.