Dynamic Modeling And Vibration Analysis Of Two Stage ISD Suspension System

The vehicle suspension system plays a very important role in vehicle damping performance.The research on vehicle suspension system has always been a hot issue in automotive engineering.Based on the theory of mechanical and electrical similarity,a two-stage ISD suspension structure with "Inerter-Spring-Damper"(ISD)in each stage of vehicle suspension structure is proposed,which is based on the characteristics of inerter similar to capacitor,allowing high-frequency signals to pass and blocking low-frequency signals to pass.It breaks through the limitation of traditional suspension structure system on the improvement of damping performance,and helps to realize the automotive damping technology further improvement of operation.The suspension system can have good damping performance in the whole frequency range by using the damping characteristics of spring,inerter and damper.The two-stage ISD suspension system effectively coordinates the contradiction between vehicle ride comfort and stability,and has good comprehensive damping effect.Therefore,aiming at the dynamic modeling and vibration characteristic analysis of two-stage ISD suspension system,the theoretical system of vehicle suspension is further improved,which has important research significance.Taking vehicle suspension system as the research object,this paper establishes two-stage ISD suspension system dynamics model,and explores the dynamic characteristics of suspension system under various vehicle body models,different types of excitation signals,different driving speeds,different road surface roughness and other factors,specific research contents are as follows:(1)This paper presents a two-stage ISD suspension structure which is different from the existing common vehicle suspension,and establishes the motion differential equation of the quarter vehicle system model.The superiority of the suspension performance is verified by the transfer function gain index.Firstly,based on the mechanical and electrical similarity theory of inerter,a two-stage ISD suspension structure is proposed,which is different from the existing common vehicle suspension.Secondly,the motion differential equation of the quarter vehicle system model of the two-stage ISD suspension is established.Finally,the suspension proposed in this paper is verified by comparing the transfer function gain index of the traditional suspension and the existing ISD suspension advantages of frame structure performance.(2)Based on the quarter vehicle system model of two-stage ISD suspension,the transmission characteristics,power spectral density and dynamic response of the system under impulse input are analyzed.Firstly,the influence of suspension structure parameters on the transmission characteristics of vehicle suspension system is analyzed.Secondly,the influence of inertia coupling effect,vehicle speed and road roughness on the power spectral density of vehicle suspension system is analyzed.Finally,the dynamic response of vehicle suspension system under the road pulse excitation caused by road construction and environmental factors is analyzed.(3)The dynamic model,performance evaluation index model and various types of road excitation signal model of two-stage ISD suspension vehicle system are established.Firstly,the whole suspension system model is established,and the whole suspension system dynamics model is built.Then,the performance evaluation index model is established,which is divided into direct performance evaluation index model and indirect performance evaluation index model.Finally,the incentive model of uneven road is established,mainly including periodic signal incentive model,dual frequency fitting signal incentive model,deceleration band signal incentive model excitation model,random road excitation model.(4)Through the comprehensive performance evaluation index of two-stage ISD suspension vehicle system,the vibration response characteristics of vehicle system under different excitation types are analyzed.Firstly,the influence of the phase difference between the left and right tires under the periodic signal excitation on the dynamic response of the vehicle system is compared and analyzed.Secondly,based on the dynamic response of the vehicle system under the dual frequency fitting signal excitation,the influence of the angular frequency on the vibration response characteristics is discussed.Finally,the vibration response characteristics of the vehicle system under the deceleration belt signal excitation and the random signal excitation are analyzed,and the quantitative surface is obtained the improvement degree of damping performance of suspension structure proposed in this paper is indicated.(5)The dynamic response analysis of two-stage ISD suspension vehicle system under different road condition parameters is completed,and the influence rule of road condition parameters on the improvement of ride comfort of two-stage ISD suspension vehicle system is obtained.Firstly,the dynamic response of the suspension system under different excitation amplitude,vehicle speed,deceleration belt width and height is analyzed.Secondly,the influence of road condition parameters such as different excitation amplitude,vehicle speed,deceleration belt width and height on the ride improvement of the two-stage ISD suspension vehicle system is explored.Through the study of two-stage ISD suspension system,it can be concluded that the two-stage ISD suspension system has better low-frequency damping performance and comprehensive damping performance than the existing vehicle suspension system.The specific performance improvement is as follows:the two-stage ISD suspension system can effectively suppress the vibration response generated by the road excitation;under various types of road excitation,the two-stage ISD suspension system always maintains a high degree of performance improvement;the two-stage ISD suspension system has stable dynamic damping performance when the road condition parameters change.