Research On Terminal Trajectory Planning Of Ball And Tube Intersecting Welding Robot

Spherical pipe intersecting line welds,as a relatively common spatial weld,are mainly complex curve welds generated by the intersection and connection of spherical shells and circular pipes.Spherical pipe intersecting line welds often exist in the fields of pressure vessels,nuclear power,and other fields,and their welding quality is a direct impact factor on the service life of pipelines and pressure vessels.Although welding robots have developed rapidly at present,their use in the field of ball and tube intersecting line welding is still relatively weak.At the present stage,the welding of ball and pipe intersecting lines in China is still in the stage of robot teaching or manual welding,both of which are relatively backward and unable to meet the requirements of high-quality and high-efficiency welding.Therefore,in order to reduce workers’ work intensity,improve welding quality,and meet the domestic manufacturing market demand,it is of great significance to develop high-quality and efficient automatic welding robotic arms to promote the development of the manufacturing industry in the welding field in China.This paper takes the intersecting line weld of ball and pipe as the research object,and uses ABB IRB1410 robot for trajectory planning and optimization.Robot Studio simulation and actual welding experiments prove the effectiveness of the method.The research was conducted as follows:(1)Based on the structure and size of ABB IRB1410 welding robot,a D-H model of the robot is established.Through the description of the rigid body posture and coordinate system transformation,homogeneous equations are established,and the forward and inverse kinematics equations of the robot are solved.According to the Monte Carlo method,a point cloud diagram is simulated and analyzed in MATLAB software for the workspace of the robot.(2)Establish a mathematical model for the weld seam of the intersecting line of the ball and pipe,and analyze three situations of the intersection of the ball and pipe.Based on the mathematical model of ideal intersecting line welds,equations are established to estimate the geometric characteristics of the intersecting line(curvature,distortion,minimum radius of curvature,and arc length);Establish a welding posture model,interpolate the weld path points using NURBS curves,and then use MATLAB to simulate the weld curve,achieving the trajectory optimization of the ball pipe intersection line weld.(3)Multi-objective optimization of the welding effect of the robot is carried out.A normalized objective function is established by constraining the speed,acceleration,and acceleration of each joint of the robot arm by comprehensively considering the time,energy consumption,and pulsating impact performance indicators.A multiobjective adaptive particle swarm optimization algorithm(CPSO)with chaotic optimization is proposed.In the mathematical model of the working trajectory,quintic NURBS curves are used to interpolate the path points at the end of the robot arm.The chaotic optimization method is integrated into the particle swarm optimization,and a dynamic weighting method is proposed to select the globally optimal particle with the highest fitness;The adaptive mutation rules of particle swarm are improved through external archiving,resulting in more excellent particles,reducing the possibility of local optimization,improving computational efficiency,and improving the Pareto value set space.Through software simulation,under known constraints,the optimization algorithm can achieve multi-objective optimization of the target trajectory,ensuring that the welding robot arm runs along the optimal path.(4)In Robot Studio software,ABB IRB 1410 robot and welding gun working unit are called to establish a workstation,run the prepared Rapid program,record and analyze the robot’s joint displacement data and TCP trajectory.The simulation results show the effectiveness of robot modeling and weld trajectory planning and optimization.After pre-treatment of the ball tube material,the actual welding operation was passed.The actual welding effect is good,the weld seam is smooth,and the fitting degree between the welding gun head and the weld trajectory is good,meeting the preset processing requirements.