Simulation Studies On High Frequency Coupling Vibration Of The Suspension And Steering System

With the continuous growth of peopler for the requirements of the car,consumers are not only concerned about the reliability of the car,but also concerned about the car driving experience.Vehicle vibration is one of the main performance that affects the driver driving experience directly on the driver.And steering wheel jitter is an important factor influencing the driver's driving experience.The vibration of the suspension and steering system caused by the high-speed shimmy of the front wheel and the vibration of the steering wheel have seriously affected the driver's driving experience.And it will bring a lot of bad problems,such as handling,a adrift of a vehicle toward the shoulder of road,shorten of parts service life,etc.Based on the resources of the research group and the advantages of cooperation with the enterprise,this paper uses ADAMS to simulate the high frequency coupling vibration of the suspension and steering system caused by the high-speed shimmy of the front wheel.The specific work of this paper is as follows:1.Firstly,this paper introduces the basic parameters of MF nonlinear tire model and the method of parameters identification.Then,the parameter identification of the tire model is carried out according to the test data.Finally,the tire model is used to extrapolation simulate the model to ensure the accuracy of the model under any conditions of arbitrary load.This lays the foundation for the following non-linear tires matching the vehicle model.2.Firstly,based on the nonlinear tire model,the single-degree-of-freedom model of the front wheel shimmy and the dynamic equations of the shimmy are established,in the case of ignoring the specific structure of the suspension system and the steering system.And then a comparative study was carried out in Simulink software and ADAMS software.Finally,in order to analyze the work that the tire force done in the self-excited shimmy pendulum,two movements concepts of the forced tire shaking and the forced tire side slip are put forward.By comparing the two different tire movement patterns' characteristics,the tire forces of the two movements are analyzed and the results were analyzed.The results of the analysis show that the tire is doing positive work in the shimmy,and the energy is absorbed by the tire's negative damping effect,therefore,the tire self-excited shimmy occurs.3.High-frequency Coupled Vibration Test of Suspension and Steering System.First,through the first test in the test ground,high-speed shimmy car was initially selected.Then based on the frequency domain analysis of the experimental data,it was found that the vibration frequency at each speed was not significantly different from the number of the tire turns per second.And then in order to eliminate other interference factor to get better control test results,in the indoor vehicle drum test bench,the unilateral 40 g unbalanced mass test was carried out at different speeds,which provides data support for the fifth chapter Model validation.Finally,the test data are analyzed by frequency spectrum to determine the main vibration direction of each measurement point vibration,which provides the direction for comparing the simulation data with the experimental data in Chapter 5.4.The establishment of the high frequency coupling vibration model of the suspension and steering system was introduced.First,the model-related issues were introduced,including the treatment of the drum road model,the tire inertia treatment,the vehicle fixed mode simulation processing,suspension nonlinear stiffness and damping factors and the simulation of the bushing.And then the modeling of the coupled multi-body dynamics model on the Suspension and Steering System is established.Second,the model simulation data and test data were compared.The results show that the vehicle simulation curve is a good agreement with the experimental data curve at a speed of 90 km / h,100 km / h,110 km / h.This shows that the accuracy of this model is very good.Finally the tire high speed uniformity analysis was carried out based on the model.The results show that the fundamental frequency simulation value is very close to the measured vibration frequency at each velocity section.Whether with imbalance in the quality of the role of the tire or ont,the front wheel shimmy components will be produced,just shimmy effect is obvious or not.When the tire geometry is not uniform or uneven stiffness or the combined effect of the two,and the tire force fluctuates to a certain value,it has a great influence on the high speed shimmy,and the steering wheel jitter is very obvious.