Research On Multi Body Dynamics Of Three Ring Reducer With Small Tooth Difference For Aero Electromechanical Actuator

With the continuous innovation in the field of Aerospace Engineering Technology in China,higher requirements are put forward for the performance of precision transmission mechanism.Electromechanical actuator is an advanced control device integrating servo motor and precision transmission mechanism,which plays an important role in spacecraft.In this paper,according to the requirements of a certain type of aircraft canopy elevator actuator on the transmission mechanism,the multibody dynamics of three ring reducer with small tooth difference is studied.Firstly,the structure principle of the cockpit cover and the gear reducer system are introduced.In order to solve the problem of complex parameter calculation and low precision in the design process of three ring reducer with small tooth difference for actuator,Matlab is used to compile the calculation program to obtain the accurate structural parameters such as displacement coefficient.According to the calculation parameters,CAXA is used to accurately draw the gear tooth profile,and the assembly conditions of the inner tooth plate are analyzed.Then the three-dimensional assembly model of the three ring reducer with small tooth difference is established in CATIA.Secondly,the dynamic force of three ring reducer with small tooth difference is analyzed.The whole transmission system is divided into internal gear plate subsystem,input shaft subsystem and output shaft subsystem,and the dynamic models of each subsystem are established.Considering the elastic deformation of components,the elastic deformation coordination equation of planetary bearing and internal gear plate is established.The dynamic model is solved by MATLAB,and the load curves of gear pair,planetary bearing and shell support bearing with crank angle θ are obtained.Then the influence of input parameters,structural parameters and stiffness coefficient on the dynamic performance of three ring reducer with small tooth difference is analyzed.Then,with the help of ANSYS and ADAMS software,the rigid flexible coupling model of three ring reducer with small tooth difference is established,and the multi-body dynamics simulation analysis is carried out.Based on the Hertz theory,the contact stiffness and damping are calculated,and the dynamic response of the cockpit cover unlocking,folding opening,folding closing,locking and braking process driven by the three ring small tooth difference reducer is explored in detail.The simulation results are combined with the FFT spectrum analysis program written by MATLAB to analyze the frequency response characteristics.Finally,the modal analysis and harmonic response analysis of the three ring reducer with small tooth difference are carried out in ANSYS Workbench software,and the natural frequency,vibration mode and frequency response characteristics of the system are obtained.The analysis of inherent characteristics provides a reference for avoiding resonance and fault diagnosis of three ring reducer with small tooth difference in aviation engineering.Research results: through the calculation program of gear parameters,the accurate modification coefficient and other parameters are obtained.By analyzing the dynamic model of three ring reducer with small tooth difference,it is concluded that the input torque,speed,transmission ratio,stiffness of bearing and inner tooth plate have great influence on the transmission stability.Through rigid flexible coupling simulation analysis,the dynamic response and frequency response characteristics of the reducer under different working conditions are obtained.Through the analysis of the natural characteristics,it is concluded that the deformation is mainly concentrated on the inner tooth plate,the natural frequency of the system is far away from the rotation frequency and meshing frequency of the gear,and the external exciting force frequency has a great influence on the first and fifth natural frequencies of the system.