Aim\ In order to optimize structure and controller of robot

dynamic characteristics of a spot welding robot is analyzed with a method of experimental modal analysis. Methods\ Law of variations of modal parameters of the robot at different structural configurations as well as its lower orders of natural frequencies under two typical structural configurations is found out. Results\ Relatively weaker areas in the strength of the robot frame are carried out. Conclusions\ It is pointed out that the distribution of the mass and stiffness of the robot should be reasonable

and an optimized design method is demonstrated.