| With the gradual improvement of the structural design of wave generators,flexible wheels,rigid wheels and the theoretical research on the processing and manufacturing of harmonic gears,the application of harmonic gear drives has also expanded from the field of aerospace technology to industrial robots,satellites and other mechanical fields,and has a wide range of applications.However,due to the particularity of its transmission mechanism,the dynamic performance of harmonic gears has become one of the main obstacles to its development.In order to apply the harmonic drive technology to the industrial field with higher requirements on its performance,according to the different goals of studying the actual system,a theoretical model with a moderate degree of complexity and the realization of the research purpose is established.Through the study of its dynamic characteristics,the dynamic performance of the actual system is finally improved.The research on harmonic drive dynamics has high theoretical significance and practical value.This thesis takes the harmonic drive system as the research object,establishes the corresponding equivalent system dynamics model,and completes the analysis of the dynamic characteristics.The main researches are as follows:(1)The modeling and parameter identification of nonlinear factors such as kinematic error and comprehensive stiffness existing in the harmonic drive system are completed by means of experiments.According to different research objectives,the corresponding analysis model is established to simplify the actual harmonic system.Specifically:(1)Research from the perspective of the whole system,establish an equivalent system bending-torsional coupling vibration model,The internal nonlinear factors of the harmonic system are equivalent to those caused by the meshing of the above-mentioned equivalent system model.(2)Research from the perspective of transmission of the internal structure of the system,establish an equivalent internal structure transmission model,In the model,the torsional stiffness of the flexible wheel,the support stiffness and support damping of the flexible bearing,the meshing stiffness and meshing damping of the gear teeth,and the nonlinear characteristics of the damping factors are considered.(2)The numerical method is used to solve the flexural-torsional coupled vibration model of the equivalent system,and the influence of different bifurcation parameters on the motion state of the system is studied.The results show that:(1)The input speed,kinematic error and backlash are all important parameters that affect the bifurcation characteristics of the system,and the bifurcation modes of the system entering chaotic motion with different parameters are also rich.(2)The increase of relative damping ratio and static load will lead to the weakening of the chaotic bifurcation phenomenon of the system and improve its working stability.Experiments verify the correctness of the theoretical model and theoretical analysis.(3)The dynamic equation of the equivalent internal structure transmission model of the harmonic gear is solved by numerical method,and the influence degree of different stiffness and damping components on the system response is studied.The results show that:(1)The stiffness factor has a certain influence on the dynamic characteristics of the system,and the system response behaves differently with the change of different stiffness within a certain range.According to the stiffness sensitivity analysis,the torsional stiffness of the flexible wheel is the most sensitive dynamic parameter.(2)The system response is also affected by different damping components to a certain extent,but the nonlinear components of support damping have little influence on it.According to the damping sensitivity analysis,the linear component of support damping is the most sensitive dynamic parameter.The experimental results also verify the correctness of the theoretical model and theoretical analysis. |
PDF Full Text Request