Study On Welding Path Planning Method Of Robot Intersecting Line Welding Seam

Welding robot has gradually become an important part of the automatic production line.At present,the welding robot in use mainly focuses on spot welding,relying on manual teaching and off-line programming to complete the welding task.Due to the difficulty in teaching and programming robot arc welding with complex trajectories,and the problems such as the end jitter of welding gun,velocity fluctuation,and singularity in the process of trajectory planning,the application of robot arc welding is relatively low.The research of arc welding robot trajectory planning and optimization method is of great practical significance to the practical application of arc welding robot.In this paper,the welding seam of the intersecting line of circular pipe is taken as the research object,have conducted a research:(1)According to the original weld point data of the crossing line,NURBS curve was used to fit the weld curve,and the iterative method was adopted to determine the minimum number of control points satisfying the contour error.In this paper,a method for solving interpolation point parameters with low velocity volatility is proposed.Firstly,the first order Taylor formula is used to solve the next interpolation point,and then the Newton method is used to iteratively reduce the velocity volatility.In this paper,a method of welding torch attitude planning is presented,the theoretical intersecting tube model is used for welding torch attitude interpolation,and the calculated welding torch attitude is corrected according to the deviation between the theoretical intersecting line and the actual welding seam.The proposed method was verified by Matlab.The results show that the weld curves obtained by this method meet the requirements of contour error,interpolation point and welding gun attitude.(2)According to the structure size of ABB IRB1410 robot studied,the robot kinematics model was established by D-H method,and the solution method of closed solution of robot inverse kinematics was derived.On this basis,the inverse solution screening method of robot is designed according to the restriction conditions of inverse solution such as the range of motion of joint Angle and the position of singularity.The robot kinematics model IRB1410 was established in Matlab,and the closed solution method of robot inverse kinematics and the Matlab program of inverse solution screening method were written.The correctness of the method was verified by using the Robotic Toolbox in Matlab.(3)Considering the actual operation requirements of the robot,solve the layout problem of welding parts for the intersecting line welding seam of the robot.Taking energy consumption and robot maneuverability as optimization objectives,joint motion range,joint velocity range,singularity and robot workspace range as constraint conditions,the mathematical model of workpiece layout was established.Based on the genetic algorithm,we designed the solution process of the workpiece layout problem,wrote related programs in Matlab,completed the solution of the workpiece layout problem,and verified the correctness of the mathematical model and solution method of the workpiece layout optimization problem.(4)Build the simulated actual robot work unit in Robot Studio software,write the Rapid program and run it according to the robot inverse solution obtained in the preceding part of the text,and record the six-axis displacement data and TCP trajectory of the robot in operation.The simulation results show the correctness of weld curve construction,robot modeling and solution.Then,on the basis of preprocessing of pipe fitting,the robot welding experiment of intersecting line weld was carried out.The experimental results show that the proposed method can be used in practical robot welding.