Research On The Method Of Error Model About A3 Spindle Head Based On D-H Method

This dissertation deals with the requirements of aerospace aluminum alloy large thin wall structure,which is supported by the National Natural Science Foundation of China and the Natural Science Foundation of Tianjin,facing a new type three degree of freedom parallel spindle head named A3 spindle head,and systematically studies problems including design of hardware limit protection device,error modeling with motion pair error and research of error identification method.The following achievements have been obtained.Hard limit protection device.The inverse kinematics model is established,and combined with the limitation getting the workspace and task workspace.With the aid of relationship between A3 spindle head position and motion pair position,the hard limit protection device controlled by PMAC is designed,and it can keep A3 spindle head working in the workspace anytime.Geometric error modeling.Based on the motion pair error,by using DenavitHartenberg method,the geometric error model including the axis deviation error,angle error and clearance error can be established.Based on the error model the relationship between A3 spindle head's pose accuracy and motion pair error is established by the simulation results.It could be used for improving the accuracy of A3 spindle head by the limitation of motion pair manufacturing accuracy.Error identification method.Using Double Ball Bar,error identification model of A3 spindle head is established by using vector transfer method,based on a simple measurement method,the best measurement location is proposed which is determined by the condition number of identification matrix.To overcome the poor condition of identification result,ridge regression method is used to optimize the identification result,which is verified by the simulation result.The research results have important significance to improve the working performance and engineering application of A3 spindle head.