Dynamic Characteristics Analysis Of Spindle System Based On Response Surface And Genetic Algorithm

High-speed motorized spindle is one of the key components of the machine tool,whose working condition,useful lifetime,and machining accuracy directly determines the working performance of the machine tool.Meanwhile,as the precise electromechanical-hydraulic integration product,it is difficult to directly evaluate the performance of the motorized spindle through the engineering experience.If the dynamic model of motorized spindle can be established in the research stage to obtain its performance,it will be of great benefit to shorten the design and production period.Therefore,this article studies the dynamic modeling optimization and dynamic characteristics of the high-speed motorized spindle.Based on rotor dynamics theory and rolling bearing tribology,this paper divides the spindle system modeling into three parts: angular contact ball bearing modeling,tool holder-spindle joint modeling,and spindle system modeling.And then,the parameter correction method of the spindle joint part is proposed combining response surface and genetic algorithm,and a spindle system model with corrected parameters is established.Finally,the effectiveness of the method is verified by the experimental results.The specific research content of this paper is shown as follows:Based on Hertz contact theory,the rolling element coordination equations considering preload are established,and the quasi-static model of high-speed angular contact ball bearing is established.The simulation program is written by MATLAB to explore the relationship between the bearing speed and the bearing stiffness,rolling element load.According to the structural characteristics of the high-speed motorized spindle,the structure of the high-speed motorized spindle is simplified,and the finite element model of the spindle is established based on the Timoshenko beam element theory.And then,the tool holder spindle joint model is established by using theoretical calculation method.Combined with the angular contact ball bearing model in Chapter 2,a complete dynamic model of the spindle system is established,and the influence of joint parameters on the natural frequency of spindle system is discussed.The acceleration force frequency response function and natural frequency of real spindle system are tested in field test,which are taken as optimization objectives.Taking the parameters of the tool holder spindle joint as the input parameters and the simulation natural frequency of the spindle system as the output parameters,the corresponding response surface model is established.The multi-objective optimization algorithm is used to optimize the parameters of the tool holder spindle joint.The natural frequency and frequency response function of the optimized spindle system model are solved,and the accuracy of the proposed model is verified by the experimental results;In the optimized model of the spindle system,the influence of dynamic balance level of different parts on the spindle end response is analyzed.Meanwhile,in order to analyze the working condition of the spindle system,the multi-stage processing signals of the spindle are collected at the same speed and different cutting depth,which are then loaded to the spindle system model as the input loaded to calculate the spindle speed.The end responses of the system under different working conditions are analyzed,The relationship between the input load and the end response is also explored.