Structural Analysis Of Arc-welding Robot Based On Finite Element Method

Welding is a fundamental process for most manufacturing projects. Robotic welding is becoming a common sight in industrial facilities and it has several advantages: Faster welding cycle times, no breaks in production. Better quality weld product and less wasted material. Removes workers from hazardous work environments. More precision, flexibility to reach hard-to-reach spots.Saving money through speed, quality production and fewer labor costs.And arc welding robot technology involves automatic control theory, machinery and electronics, computer science, materials science,bionics,etc. After decades of research and development, arc welding robot technology has been relatively mature and its application also is very extensive. The application mainly concentrates in the automobile, motorcycle, bicycle racks, pressure vessel, engineering machinery, hardware products, etc. However, in the domestic arc welding automation market, foreign arc welding robots are still in the dominant position.According to a report published by the International Federation of Robotics, IFR, September 2011,robot supply to china will further surge, and china’s growth in robot installations will surpass other countries to the top of the robot market worldwide. Representing nearly 20% of all robotic applications, arc welding robot is one of the most common functions in industry today. As many foreign robot companies get a large share of china’s industrial robotics market nowadays, it is extremely urgent to develop industrial robot with proprietary intellectual property rights and master the core technologies.The beginning of this paper studies the influence of different finite element modeling methods on the accuracy of finite element analysis. After the studies, the general principles of element selection and meshing strategy have been given. On the basis of reverse engineering technology, parametric modeling technique and finite element method theory, 3D modeling and structural analysis based on Pro/E and ANSYS are utilized to simulate the deformation and stress distribution of the robotic arm which is in a limit position. Especially, the simulation also take into account the impact of bolt pre-tightening force and inertia force.After the virtual model of arc welding robot is built, this paper analyzes the dynamic capabilities of the robot’s arm and overall mechanical structure of the robot, details include modal analyses(pre-stress and none pre-stress) and flexible dynamic analysis. On the basis of robot inverse kinematics, the time-varying loads of each joint of the arc welding robot is captured by ADAMS. Then the flexible dynamic analyses module integrated in ANSYS provides us with the ability to determine the dynamic response of the arc welding robot system under that dynamic loads condition.At last, according to the results of the above analysis, the weight of arc-welding robot’s arm is successfully reduced through size and topological optimization design.