Research On Drilling Pose Of 6-DOF Industrial Robot

As the robot drilling technology with high degree of automation,the stability of work performance,good reachability and other advantages,which were widely used in the aircraft manufacturing.However,the tandem 6-DOF industrial robots have lower system stiffness compared with the stiffness of CNC machine tools,which is not conducive to improve the quality of holes.Therefore,it is necessary to improve the performance of the robot end stiffness,in order to obtain high-quality holes.In this paper,numerical simulation and experimental research methods were adopted to analyze the impact of pose on the robot end stiffness of the rules,by optimizing the pose to improve the robot end stiffness performance.The results of this paper have practical engineering application value in terms of basing on the optimal principle of the overall line stiffness of the robot end to select better pose to improve the quality of holes.Firstly,builed up equivalent mechanism model of robot according to the features that the origins of FANUC R-2000 i robot's connecting rod coordinate system are in the same plane.What's more,the geometric model of robot drilling pose was established according to the actual situation of robot drilling.The drilling pose of four kinds of robots were obtained through the "plane geometry method" proposed in this paper,and the correctness of the method was proved by experiments.Secondly,the robot's overall transmission system is decomposed into six independent subsystems,and the theoretical stiffnesses of the six joints of the robot were calculated based on the principle of equivalent stiffness and the empirical formula for calculating the stiffness of critical components.Thirdly,the influence of pose on the robot's end stiffness was analyzed by numerical simulation and experimental research.When the robot is in the same pose,the stiffness of the robot in the y-direction is greater than that in the x-direction and the z-direction.Poses has greatest influence on the stiffness in the y direction of the robot end,and has the least influence on the stiffness in the z direction.Among robots of four kinds of pose,the robot of the fourth pose has the highest rigidity in the x direction,the y direction and the z direction,and the overall line stiffness performance is more superior than that of the other three pose robots.In addition,modal analysis for robots of different poses was carried out.Finally,a experimental platform of robot drilling was set up.The key parameters of the holes end effector and the corresponding drilling parameters were determined Drilling experiments were carried out on robots with different pose.What's more,the roundness of the hole and diameter error were used to evaluate the quality of robot drilling.At last,the experimental results suggest that appropriate robot pose will help to improve the drilling quality based on the principle that the overall line stiffness performance of the robot end is optimal.