Dynamic Response Of A Compound Planetary Transmission System Of Space Manipulator Joint

Along with the development of aerospace technology,the level of stability and safety of the space manipulator is increasing,which puts forward higher requirements for the space manipulator joint system.Planetary gear transmission system,is widely used in large-scale space manipulator joint equipment with long life,has lots of advantages such as large capacity,high reliability,compact structure,large transmission ratio,and so on.Therefore,the dynamic characteristics of compound planetary gear transmission system is studied in this thesis,in order to provide guidance for designing the joint of the space manipulator with excellent dynamic characteristics.In order to analyze the dynamic characteristics of transmission system,the dynamic model of the system should be established,considering the nonlinear factors such as meshing stiffness.Through the machining principle of rack machine gear,the exact tooth profile curve was deduced.Based on APDL,the entity gear meshing model with ideal tooth profile was built.After the entity model of gear was meshed preliminary,the mesh of the contact area is refined.By calculating the meshing stiffness of gears with different phases,the time-varying meshing stiffness of gears is obtained,the variation of meshing stiffness under different torque conditions was also analyzed to provide accurate kinetic parameters for planetary gear dynamics research.A modified translational-torsional coupling model of composite planetary gear transmission system,was developed using lumped parameter method,the component supporting stiffness,meshing stiffness,damping,backlash and other factors was considered.Based on the modular method,a general four-stage-modular-model is established,and the nonlinear dynamic differential equations of the compound planetary gear transmission system are generated by the integrated module.Based on the modular theory,the natural characteristics of composite planetary gear transmission system were studied.The mass matrix and stiffness matrix of the transmission system are divided into three modules according to the transmission type,and a universal program for calculating natural characteristics was builded.Taking the composite planetary transmission system of the space manipulator joint as an example,the natural frequency and vibration vector were calculated,and the parameter sensitivity of the natural frequency was analyzed.The dynamic characteristics of compound planetary gear system were analyzed.The dynamic response of the transmission system was solved by numerical integration method.Using MATLAB’s GUI,a modular dynamic simulation platform for compound planetary gear transmission system of space manipulator joint equipment was designed.The modular dynamic simulation platform of the transmission system includes the establishment of dynamic model and the calculation of dynamic characteristics,and the applicability and feasibility of the simulation platform were verified by using composite planetary gear transmission system as an example.