Research On Orbital Motion Control Of Pipeline All-position Welding Robot Based On BLDCM

In long-distance oil and gas transportation,oil and gas pipeline transportation is the main transportation method,and the connection of oil and gas pipelines must be completed by welding.With the increasing in oil and gas demand,the diameter and wall thickness of oil and gas pipelines are gradually increasing.The number of workers required for welding during welding has increased,the working time has become longer,and the welding environment has become more complicated;while manual welding and semi-automatic welding are due to heavy workload.,Time-consuming,laborious,low efficiency and other shortcomings,it is difficult to carry out long-term effective welding.In order to solve the above problems,pipeline fullautomatic welding began to be widely promoted,and pipeline all-position welding robot is the main tool for pipeline automatic welding.In complex environments,long-distance,largediameter,thick-walled oil and gas pipeline welding is easy to install.,It requires less labor,convenient operation,fast welding speed,and high welding efficiency.It is very popular.However,in view of the shortcomings of the traditional pipeline all-position welding robot based on stepper motors and DC servo motors,such as the fixed orbit motion control drive device,the structure is simple,the control is rough and unstable,and the anti-interference ability is poor.Drive control method based on brushless DC motor.This method addresses the shortcomings of traditional pipeline all-position welding robots in orbital motion,such as long start-up time,slow speed control response,insensitive speed change,large torque pulsation,etc.,as well as variable parameters and multiple disturbances during the motion process,which cause the welding wire to not contact the molten pool.Complete,uneven weld fill,unsightly weld bead formation,false welding and missing welding,etc.,have reduced the welding quality;therefore,a discontinuous intelligent control method combining Improved fuzzy sliding mode control(IFSMC)with fuzzy PI is proposed.Realize double closed-loop control;among them,discontinuous intelligent control refers to the control with switching characteristic structure that uses the improved fuzzy sliding mode control system to change over time;the inner loop is the current loop control based on fuzzy PI,and the outer loop is based on the improvement The speed loop control of fuzzy sliding mode control,the drive system adopts SVPWM control technology to control the brushless DC motor.This control effectively reduces the external disturbance of the orbital motion system and increases the response speed and robustness of the system.In this paper,aiming at the problem of speed setting and moving speed range transition under variable load,variable speed,and variable welding mode,a tracking setting system using subregional fine target speed is proposed for the follow-up system.This system effectively divides the full position welding of pipelines.The range and precise feedback mechanism of the robot in different welding modes,and each area sets and monitors the operating response speed of the welding speed according to the welding quality.After simulation analysis and testing by building an experimental platform,the entire control system has the functions of parameter self-tuning and self-adjustment during the welding process.The pipeline all-position welding robot has smooth speed transition,fast variable speed response,good robustness,and stable and reliable pipeline all-position welding.