Research On Multi-objective Optimization Of Planetary Transmission System Of Wind Turbine Gearbox

This project is based on the National Natural Science Foundation project "Ultra-power multi-planetary flexible pin wind turbine gearbox load sharing mechanism and configuration research(51405048)",aimed at the research on the optimization design method of wind turbine gearbox planetary gear transmission structure,The multi-objective optimization method is used to reduce the spatial size of the planetary gear system of the wind turbine gearbox,improve the system power density,and reduce the vibration shock during the operation of the system,thereby improving the dynamic performance and reliability of the wind turbine gearbox.Planetary gear transmission has many advantages such as high transmission power,high power transmission efficiency and compact structure,and has been widely used in wind power generation,shipbuilding,aerospace and other fields.Due to the high load density of the system line and the strict requirements on the design size,it is necessary to consider not only the transmission efficiency of each component,the transmission capacity and the geometric size,and the positional relationship between the spatial position,but also the design parameters of each component during operation.Dynamic performance and the influence of meshing contact,conventional traditional design methods are often difficult to achieve the desired engineering practical results,so discussing the optimization design method has a good theoretical and practical significance.In this paper,a large wind turbine gearbox planetary gear transmission system is taken as the research object,and the dynamic performance of the planetary gear system based on the space size,transmission efficiency,tooth surface contact temperature,gear tooth loading and dynamic meshing force of the gear pair is based on the gear.Multi-disciplinary intersection theory,such as meshing principle,mechanical dynamics,thermodynamics,intelligent algorithm and response surface optimization method,the multi-objective optimization of wind turbine gearbox planetary gear transmission system is studied by theoretical calculation and analysis method.Two optimization methods are adopted.The multi-objective optimization design of the planetary gear system from different angles aims to design a planetary gear system with lighter structure,higher transmission efficiency,smoother transmission,less meshing impact and better power performance.The main research contents of the thesis are as follows:1)The factors of meshing phase,time-varying meshing stiffness and comprehensive error of the system are studied.The dynamic equations of the planetary gear system including the above excitation are derived by the lumped parameter method.The time-varying mesh stiffness of the system is analyzed for the characteristics of the planetary gear system.The damping and the integrated error are used to derive the solution method of the system dynamics equation,and the vibration response and mode of the system are solved.2)The planetary gear dynamics equation is solved to obtain the vibration response of each component and the dynamic meshing force of the gear pair.The three sets of parameters are analyzed by the partial conductance method: the sensitivity of mass,stiffness and damping to the response of the planetary gear system.The influence of parameter variation on r-p dynamic meshing force and s-p dynamic meshing force is discussed for the parameter with the highest comprehensive sensitivity.3)Using the improved particle swarm optimization algorithm,considering the installation conditions,adjacent conditions,transmission conditions,bending strength and other factors of the planetary gear system,it is used as the constraint of the optimization function,with the number of teeth,modulus,tooth width and displacement coefficient.As a design variable,the static multi-objective optimization design based on intelligent algorithm is applied to the planetary gear system with the minimum center distance,the highest efficiency and the smallest volume as the multi-objective optimization function.Compared with the PSO,APSO and D-APSO algorithms,the optimization calculation speed and optimization effect of the planetary gear system are compared.4)Using the response surface optimization method,considering the influence of the planetary gear system parameter variation and the profile modification amount on the dynamic meshing force and the tooth surface temperature,the gear number,modulus,tooth width and tooth profile modification amount of the planetary gear system are selected as Design variables,considering the boundary coordination conditions and strength constraints of the planetary gear system,the dynamic meshing force of the two meshing pairs rp and sp of the planetary gears and the tooth surface temperature of the sp meshing pair are used as the dynamic performance multi-objective optimization function,and the design response surface is optimized.At the sample point,the response surface analysis software Design-Expert is used to calculate the design parameters corresponding to the optimal solution of the multi-objective optimization function in the design range,and the dynamic performance of the planetary gear system before and after optimization is compared.