Research On Motion Planning Of Six Degrees Of Freedom Welding Manipulator

A new generation of intelligent welding manipulators is required to engage in welding work in confined spaces with obstacles.The obstacle avoidance path planning and pose planning of the manipulators are the key technologies.This paper takes the sixdegree-of-freedom welding manipulator as the research object.The kinematics modeling of the manipulator,the obstacle avoidance path planning of the manipulator and the pose planning are studied around the intelligent welding problem of the manipulator.The main work is as follows:(1)Kinematics of a six-degree-of-freedom welded manipulator.The mathematical model of the six-degree-of-freedom welding manipulator is established by the standard DH method.The forward kinematics equation of the manipulator is derived based on the DH coordinate system.For the most commonly designed spherical wrist manipulator in the industry,a position and Inverse motion solution method for attitude separation.(2)Planning of the obstacle avoidance path of the welding robot arm.This paper proposes an improved RRT algorithm,which combines the advantages of bi-RRT and RRT* to generate two path trees simultaneously in the initial pose and the final pose,and joins the parent node connection and node in the process of building the tree.Refactoring strategy,on this basis,introduces node expansion,lazy detection and path optimization strategies to further improve planning speed and reduce path cost.For the collision detection problem in RRT expansion,this paper simplifies the robot arm and obstacle using the bounding box model,and deduces the collision detection method of the mechanical arm and various obstacles.(3)Welding robot arm posture planning.Aiming at the limitations of the use of ordinary S-shaped velocity curves,this paper analyzes all constraints and designs a general S-type velocity planner,which is applied to linear interpolation and circular interpolation algorithms to obtain smooth motion.Track.For the attitude adjustment of the welding process,the indexes of collision avoidance,welding quality and mechanical arm motion stability are integrated,and the dynamic programming algorithm is designed to search for the optimal welding attitude sequence.(4)Experimental simulation.The algorithm proposed in this paper is simulated on MATLAB.Compared with other RRT algorithms,the proposed bi-RRT* algorithm has short planning time,high success rate and relative path.The advantage of smoothing.For pose planning,the simulation results show that the intermediate point obtained by the interpolation algorithm is correct,and the output speed curve is continuous and smooth,which meets the expected target of S-shaped acceleration/deceleration control.The searched torch sequence can avoid collision and the overall performance is better.excellent.