Analysis Of Dynamic Characteristics For Six Degrees Of Freedom Arc Welding Robot

Welding robot can obviously improve the welding quality and efficiency, lighten labor intensity, reduce the cost of production and operation technology request for workers. With the wide application, localization and industrialization of wlding robots, it has great significance for the goal which China becomes the world’s manufacturing power. Based on the SRH6B welding robot researched and developed independently by SIASUN Robot&Automation Co., Ltd, we analysed the robot kinematics and dynamics. Besides, we discussed the finite element method and modal analysis. Finally, we studied calibration experiment analysis for the robot. The main study contents and methods are listed as follows:1) SRH6B welding robot kinematics models are created by D-H coordinate transformation. Based on the results of the modeling, the robot kinematics equation is acquired. The forward kinematics solution and inverse kinematics solution of the robot were given. These formulas have been proved to be correct. Using MATLAB software platform, the kinematics characteristics of SRH6B welding robot were simulated and acquired. It provided reliable models for the dynamic characteristics of the robot in the following study.2) We established dynamic equations based on Lagrange. Using COSMOS/Motion, the dynamics characteristics of SRH6B welding robot were simulated and acquired. We simulated the process which electrode holder for arc welding robot welded both straight weld and circularity weld, drawed the robot’s dynamics characteristics. By analyzing dynamics, we provided some references and values for structure improvement, optimization and components selection of the robot.3) In this paper, we analyzed of the forced for the robot’s lower arm and the upper arm. We obtained contours of stress and displacement for them by dividing grid and computing solution by SolidWorks Sinulation. Then, we studied mode of the lower arm and the upper arm, enumerated inherence frequency of preceding six mode. The preceding six mode shapes were calculated through modal analysis.4) Finally, aiming at the robot’s geometrical structure, the error sources of influencing the robot’s absolute accuracy are analyzed. Adopting an optimized kinematics model and the differential transform method, the error model for the robot calibration was solved. After that the calibration experiments have been studied by API-T3laser tracker, the robot kinematics parameters were corrected and the robot’s position precision was improved. Therefor, the calibration model of this thesis was correct and reliable.