Performance Analysis And Structure Optimization Of Robots For Transporting Rolled Parts

With the rapid development of rail transit represented by high-speed railway in China,the demand for high-quality large axle parts is increasing,and the research on transfer robot of rolling parts production line has become a research hotspot.The shaft parts in the rolling process have the characteristics of high temperature,large mass and variable specification parameters.Accordingly,the research objectives of high temperature resistance,high stiffness,large working space and lightweight are proposed for the transfer robot.In this paper,based on a transfer robot under the national key research and development plan,the virtual prototype simulation is carried out,the rigidity and workspace of the robot are verified,and the high-temperature resistance and lightweight are studied.The main work is as follows:(1)The kinematics model of the robot is established,and the workspace is solved according to the working parameters of each drive.According to the actual working conditions,the trajectory points in Cartesian space are determined,and the joint space mapping is obtained using the inverse solution model.The trajectory planning was completed by quintic polynomial interpolation,and the performance of each driver was analyzed.(2)The dynamic model of the robot is established based on the virtual work principle,and the force(torque)input curves of each drive under the working trajectory are analyzed.Using Adams for dynamic simulation,the correctness of the dynamic model has been verified;By establishing a force balance equation between the clamp arm and the workpiece,the minimum driving force of the clamp cylinder when the workpiece is about to slide is solved,and the driving force changing of the clamp cylinder under different postures and workpiece diameters are analyzed.(3)Using Hypermesh to manually divide the global hexahedral mesh of the robot,and establishing a finite element model in Workbench,based on the steady-state thermal analysis results,thermal protection is optimized in three dimensions: thermal conduction,thermal radiation,and thermal convection.Through the determined attitude of the reclaiming point and the discharging point,the thermal coupling analysis is carried out,the robot positioning accuracy is checked,and compared with the strength under statics analysis,the distribution law of thermal stress and mechanical stress is studied.The mechanical stress distribution changes little under different analysis modes,and the thermal stress changes little under different attitudes,providing a basis for rigid flexible coupling dynamics analysis.Finally,the dynamic characteristics are analyzed.(4)A rigid flexible coupling transient dynamic model was established,and the time-domain stress distribution of the transmission components under the working trajectory was analyzed,and the strength of the entire cycle was verified.The variable density method is used to obtain the topology optimization model of the swing arm base,and the genetic algorithm is used to obtain the size optimization model of the swing arm.The lightweight design of the robot is realized.The optimized whole machine model is lightweight,and the performance is improved.