| In modern industrial production,robots are changing the past industrial processing methods,especially welding robots are more and more widely used in industrial production.With the continuous improvement of industrial welding requirements,it is difficult for independent robot systems to meet the increasingly complex welding tasks.In this paper,an eight-degree-of-freedom welding robot system composed of ABB 1410 robot and positioner is used to conduct an indepth study on the problem of complex intersecting line welds and joint space trajectory planning in its collaborative welding space.The specific content is as follows:(1)Establish a mathematical model of the intersecting line,and obtain the position data of the weld seam of the workpiece according to the size of the main pipe structure and generate the intersecting line curved weld.The robot linkage coordinate system is established by the D-H method,and the transformation form of the linkage in the space is described in the form of a matrix.Use D-H method and matrix transformation to complete the solution and verification of the forward kinematics of robots and positioners.(2)Establish the coordinate system of the robot workstation system,analyze the collaborative method of the robot workstation according to the system composition of the welding robot workstation and the relationship of each coordinate system in the robot workstation,and solve and verify the inverse kinematics of the robot and the positioner.Perform coupling and decoupling analysis on the robot workstation,calculate the welding torch space attitude and the positioner joint rotation angle of the characteristic points of the weld trajectory,and realize synchronous welding.(3)Introduce the discretization of the weld point of the workpiece and the establishment of the weld coordinate system in the welding process,analyze the coordinated motion control strategy of the robot workstation,calibrate the base coordinate system of the robot and the positioner,and obtain the transformation between the base coordinate systems Relationship,so that the collaborative welding process is unified under the robot’s base coordinate system.Taking joint trajectory planning as the research object,several commonly used joint space trajectory planning methods,such as cubic polynomial interpolation,fifth-degree polynomial interpolation,parabolic transition interpolation,and piecewise seventh-degree polynomial interpolation,are analyzed.The fifth-order polynomial interpolation algorithm is verified through the Matlab robot toolbox.The simulation shows that the displacement,velocity and acceleration of each joint of the robot are continuous without sudden changes,and the effect is good.(4)The trajectory of the robot joints is optimized through the established objective function of the minimum movement amount of the robot joints.According to the welding process,determine the best welding position of the robot to achieve a stable,continuous and safe welding.Considering the motion constraints of the robot and the positioner and the continuous welding of the robot,the obstacle avoidance function and the singularity constraint function of the robot are established,so that the welding robot can avoid the collision with the weldment,and realize the one-time continuous welding of the welding seam of the space intersecting line.Based on the multi-objective particle swarm optimization algorithm for trajectory planning research work,taking the maximum rotation angle,maximum operating speed,maximum acceleration and maximum jerk of the ABB 1410 robot as constraints,it is verified that the multiobjective particle swarm algorithm is based on the minimum joint motion trajectory planning problem Effectiveness and operability.Using Matlab to obtain the trajectory diagram of the relative motion process of each joint,its displacement,velocity and acceleration curves are smooth,the robot runs smoothly,and meets the requirements of trajectory planning. |
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