| Robot welding technology has become the main symbol of manufacturing automation technology. Using robot technology in welding production can improve productivity, ,working conditions and stability, ensure the quality of welding, and realize welding automation of mass products .This paper focused on swing welding, the main research contains kinematics analysis of six DOF arc welding robot, trajectory generation of spatial arc swing welding and the attitude planning of the welding gun, the interpolation algorithm of sinusoidal trajectory and its velocity planning. The main work is as follows.(1) Kinematics analysis of six DOF arc welding robot was studied. This paper taked Huanyan HYHJ-602 six DOF arc welding robot as the object of research. The connecting rod coordinate system of the robot was established by D-H method, then the forward kinematics and inverse kinematics formula of the robot were calculated. By setting up the model of the robot in Qt Quick software, the program of kinematics was compiled, and the forward and inverse kinematics of the robot was simulated. The results proved the correctness of the algorithm.(2) The methods of generation of swing welding trajectories were carried out. The trajectory generation methods of swing welding on straight fillet weld, space arc weld,arc fillet weld and parabolic weld based on sinusoidal swing were studied. The formula for calculating the coordinates of the interpolation points of the swing welding track was deduced. The motion simulation was carried out in Qt Quick software. The interpolation points of the swing welding trajectory were converted to robot joint angles by inverse kinematics, and the joint angles were the basis of robot motion. Simulation results verified the correctness of the swing welding trajectory.(3) The attitude planning methods of welding gun were studied. The attitude interpolation algorithm based on unit quaternion was deduced. Using and the SIMULINK module of MATLAB software and Qt Quick software,the simulation results of the three attitude interpolation methods were compared. Simulation animation and angular velocity curves of the joints showed that compared with the the other two methods, the interpolation based on unit quaternion is easier, the efficiency is higher,and the transition of the attitude is smoother.(4) The velocity planning method of swing welding of arc welding robot was studied. Taking sinusoidal swing as the subject investigated, a interpolation algorithm of sinusoidal trajectory with high accuracy was proposed. Furthermore, the speed planning of the robot was carried out. The algorithm of S-type acceleration/deceleration planning was studied, and the S-type acceleration/deceleration planning was applied to the swing welding track. The motion simulation was carried out in Qt Quick software, and the results verified the correctness of the algorithm. The velocity planning of swing welding of arc welding robot was experimentally analyzed. Taking Huanyan arc welding robot as the experimental equipment, the program was integrated into the robot to verify the correctness of the swing welding interpolation algorithm and the velocity planning algorithm.This paper completed the research of kinematics of six DOF arc welding robot,trajectory planning and velocity planning of swing welding. The research results about the trajectory planning of swing welding provided a reference for the development of welding robot in the future. |
