Dynamic Modeling And Nonlinear Characteristics Study Of Herringbone Gear Planetary Transmission System For Wind Power Booster Box

Wind turbines are commonly built in harsh environments with random wind speeds and other conditions such as dusty and wet,which leads to some degree of internal and external sources of excitation for wind turbines.However,the most critical gearing in wind turbines is highly susceptible to complex dynamical responses when stimulated by the external and exogenous environment.Therefore,a comprehensive and in-depth study of the dynamics of the gear train under internal and external excitation is of great importance to improve the stability and reliability of wind turbines,and even the study of fault diagnosis mechanisms.In this paper,we analyze and study the nonlinear dynamics of the wind power gearbox herringbone gear planetary transmission system,mainly including the establishment of the nonlinear dynamics model of the system,the bifurcation characteristics of the system under different excitation changes,and the control of the chaotic motion state appearing in the system.(1)A model with multi-degree-of-freedom translational-torsional dynamics is established to carry out the analysis of the nonlinear characteristics of the wind turbine speed increaser herringbone tooth composite planetary transmission system.Various excitations,including stiffness excitation and damping excitation,are considered in the model to analyze the gear system in depth.(2)Based on the nonlinear dynamics theory,the nonlinear characteristics of the gear system under the variations of the mesh damping ratio,the mesh stiffness coefficient and the integrated meshing error are investigated by using analytical means such as bifurcation diagram,maximum Lyapunov exponent diagram and phase diagram.The results show that with the increase of the mesh damping ratio,the planetary gear system gradually transitions from multiply periodic motion to single periodic motion,and the parallel shaft system gears gradually converge from chaotic motion to periodic motion,and the increase of the system mesh damping can suppress the appearance of chaotic motion;the time-varying mesh stiffness coefficient represents the fluctuation of the mesh stiffness,and when its value is small,such as in the range of 0.05-0.4,the When the value is small,such as in the range of 0.05-0.4,the chaotic degree of the gear system is slightly smaller,and when the value is larger,such as in the range of more than 0.4,the system appears in a complex chaotic motion.For planetary gearing system,the increase in the magnitude of the meshing error causes the system to bifurcate from single-cycle to multi-cycle motion,but when it continues to increase to a value greater than 0.3,the system will reverse the bifurcation to single-cycle motion,and for parallel shaft gearing,the increase in the magnitude of the meshing error causes the gearing system to enter a long-term chaotic motion.(3)For the problem of thermal deformation of gear teeth caused by temperature changes in gear systems,the effect on tooth side clearance is taken into account,and a comprehensive translation-torsional dynamics model that takes temperature effects into account is further developed.On this basis,we carried out an in-depth analysis and discussion to reveal the nonlinear dynamics of the gear system under temperature variation,and analyzed the bifurcation characteristics of the gear system with the variation of the mesh damping ratio and the time-varying mesh stiffness coefficient when the temperature is maintained at a certain level,using global bifurcation diagrams,etc.The results show that the gear system accounting for the temperature effect presents a richer nonlinear motion state with the change of meshing damping ratio and time-varying meshing stiffness coefficient;the gear system presents different nonlinear dynamics response at different temperatures,and controlling the system temperature in the range of 70℃-90℃ can effectively suppress the occurrence of chaotic motion as a way to reduce the vibration of the system.(4)Using the cubic nonlinear feedback control method and the applied periodic signal drive method to control the chaotic phenomenon generated in the nonlinear motion of the transmission system,the effectiveness of these two methods in suppressing the chaotic motion is verified based on the numerical analysis results.