Research On Stiffness Model Of Robot For Grinding Weld-beads Of Aluminum Alloy Train Body

The process,weld-beads of aluminum alloy train body automatic grinding,is one of the most important operation of the post-weld treatment process.For purpose of solving the problem of traditional manual grinding method,the robot workstation and end effector were designed.Because of the gravity of end effector and contact force,the robot end will produce position error,which will reduce the position accuracy of the robot.In this thesis,the research on the robot stiffness matrix was carried out.Based on the traditional procedure of weld-beads polished and processing requirement,the automatic weld-beads grinding process was designed,the layout of robot workstation was completed.According to the requirement of the workload and workspace,the robot and linear guide were chosen,the end effector was designed.The D-H model of robot was built,the forward kinematics and inverse kinematics of robot were analyzed.The workspace of robot was simulated based on Monte Carlo method,which shows the reliability of the robot selection.In MATLAB environment,the Jacobi matrix was solved.Joint stiffness matrix of the robot and end Cartesian stiffness matrix were derived in detail.The joints stiffness of robot were gained by the joint identification experiment,the reliability of result was verifled by experiment.The minimum singular value of stiffness matrix,calculated by analyzing stiffness matrix,was definied as stiffness performance index.The stiffness performance of robot in different pose was analyzed by comparing the stiffness performance index.Finally,the best working pose was found.The manipulator trajectory planning of joint space was completed by using quintic polynomial interpolation programming method.In MATLAB environment,the angular displacement,angular velocity and angular acceleration diagrams were analyzed,which prove that the trajectory planning is reasonable.