Research Of Welding Robot Equipment For The Horizontal Position In The Ship

To meet the requirements of high quality and efficiency of modern ship industry,hull welding by automatic equipment is an important method.The development and application of automatic welding equipment have reached a high level abroad,however,manual welding and semi-automatic welding are still widely adopted in our country,which lead to poor quality and efficiency in shipbuilding.In this paper,combining the urgent need of automatic welding equipment and taking the ship-used welding robot as research object,some important contents are studied,including mechanical structure,kinematics and automatic planning for multi-layer and multi-pass welding.Based on the practical requirements of automatic welding for the hull horizontal position,the functional requirements and performance indicators of the welding robot are proposed,and a lightweight track-typed five-axis welding robot is established.Its structures and working process are introduced in detail.According to structure model of the welding robot,a kinematics model based on D-H method is built,and the forward and inverse solutions of kinematical equation are illustrated in detail.Furthermore,the robot workspace is analyzed by a numerical method,which proves that the robot meets the welding range of the horizontal position.Based on the shape of practical welding seam,an automatic test algorithm to groove based on touch sensor at the end of torch is proposed,and the calculation method of groove size with two different backing plates is illustrated.Moreover,on the basis of simplified bead shape,an arrangement algorithm for multi-layer and multi-pass welding is proposed,which adopted equal contour at each layer and equal pass area at one layer,and the path points' poses of each welding bead are defined.To prove the correctness of the algorithm,bead arrangement simulation on different grooves is analyzed by MATLAB,and it lays the foundation for motion control of welding robot.According to the precision need of practical welding,the spline interpolation method is adopted to complete robot trajectory planning both in task space and joint space,and trajectory planning simulation on grooves with different cross-sections is implemented by MATLAB.Meanwhile,an automatic planning software system for multi-layer and multi-pass welding is designed.At last,a welding experiment is implemented by the welding robot.The results show that the welding seam is with good compactness and appearance,and the welding efficiency is 1~2 times higher than human,which prove the feasibility of this welding robot system.