The Design And Dynamics Research Of A Two-degree-of-freedom Planetary Reducer In Aerospace

As an important part of the aerospace craft,the actuator is the key component to control the flight direction and attitude.The redundant actuator meets the requirement of high reliability of the spacecraft.In this paper,according to the requirement of the electric actuator in a certain craft,the research of the two-degree-of-freedom planetary reducer is carried out.The structure design of the reducer is completed based on the theory of mechanical design,including gears,planetary frame,box and bearings.2D drawings and 3D virtual assembly model are drawn in CAXA and Creo.The root strength of dangerous gears is checked and the life of bearings is calculated.The finite element analysis software ANSYS Workbench was used to analyze the strength of gears and planetary frames,and the strength and axial stiffness of the box are analyzed.The rigid servo system and the flexible servo system are modeled by using the dynamic theory of mechanical system,and then establish the Lagrange equation.The switching motor and the load impact are simulated in Simulink.The multi-rigid-body model and the rigid-flexible coupling model are simulated in ADAMS.Dynamic characteristics of mesh force and output speed in time and frequency domain are analyzed.Based on the elastodynamics theory of planetary gear transmission,the vibration characteristics of gear transmission system are analyzed.The relative displacement,meshing stiffness and support stiffness of each component are analyzed.The vibration differential equation is established and the natural frequency of transmission system is solved in MATLAB.The finite element analysis software ANSYS Workbench is used to analyze the finite element modal of the input gear shaft,transmission system and reducer,and the natural frequency and modal mode are obtained.The natural frequencies can provide reference for noise reduction and vibration reduction.Finally,three tests are carried out,including transmission accuracy test,transmission efficiency test and axial stiffness test.The tests show that the performance of the prototype basically meets the requirements of the indicators.