Kinematic Reliability Analysis On Cutter-Change Robot Of Shield Machine Based On Rigid-Flexible Coupling Model

With the rapid development of high-speed railway and subway industry in China,shield machine is more and more widely used,and the cutter-change robot of shield machine has gradually become a research hotspot in recent years.In this paper,a cutter-change robot of shield machine has been designed with the reliability used as the index to conduct a quantitative analysis of the kinematic precision.It is studied mainly including the following parts based on the rigid-flexible coupling model under full load.(1)Kinematic theory analysis and simulation of cutter-change robot of shield machine.The forward and inverse kinematics equation of the cutter-change robot is established according to the standard D-H method.The workspace is solved based on the monte-carlo sampling method.Based on Matlab robot toolbox,the correctness of robot kinematics model is verified,which provides theoretical basis for subsequent error and motion precision calculation.(2)Analysis of strength and stiffness for the cutter-change robot of shield machine.Stress and deformation under full load are analyzed based on Workbench to complete stiffness and strength check.The rigid-flexible coupling model is established based on the classical interface of Ansys to provide the model basis for subsequent analysis.The dynamic stress is analyzed based on the rigid-flexible coupling model,and the model is verified by comparing with the static analysis.The results show that the dynamic characteristic analysis can more accurately reflect the real situation of the robot in motion.(3)Error analysis of the end position for the cutter-change robot of shield machine.The error theory model is established.Kinematics simulation is carried out on the rigid model of the cutter-change robot based on Adams to determine whether the motion process could meet the requirements of stability.The end position error is analyzed based on the rigid-flexible coupling model by analyzing the influence of the flexibility of the connecting rod,the magnitude of load and the motion time.(4)Kinematic reliability analysis for the cutter-change robot of shield machine.The kinematic reliability model is established according to the error theory model.The influence of joint angle error,joint angle dispersion and rod length error on the reliability of kinematic accuracy is analyzed based on monte-carlo sampling method.The kinematic simulation is carried out based on the rigid-flexible coupling model and the kinematic accuracy reliability of the model is obtained in line with the actual motion conditions.(5)Structure optimization of the cutter-change robot of shield machine.Based on Wokbench/Design Exploration module,the section size of mechanical arm is optimized.Comparing the stiffness,strength and motion reliability of the model before and after optimization,the results show that the optimization effect is fine.