Analysis of dynamic characteristics of nonlinear vehicle suspension system with five degrees of freedom

Abstract

With the rapid development of the automobile industry, the performance requirements of the automobile has been becoming higher and higher which shows the great significance of the study on vehicle suspension characteristics. Based on the structural characteristics of the vehicle, a five degree of freedom vehicle model is established. The dynamic equation of the vehicle model is listed by using the vibration law of the multi degree of freedom damping system. The simulation model of five degree of freedom linear and nonlinear system of automobile is established by using MATLAB/SIMULINK. The simulation analysis of ride comfort is carried out based on simulated nonlinear stiffness: Compared with the results of linear and nonlinear parameters, the nonlinear stiffness coefficient alpha is monotonically decreasing in -0.4∼0, which can improve the ride comfort of the vehicle. The nonlinear stiffness mainly affects the seat acceleration, the centroid acceleration and the pitching acceleration. The nonlinear system is optimized by the obtained law concluded from simulation. The results show that the performance of the suspension system can be greatly improved, the mean square root value of the centroid acceleration is reduced by 38.67 % and the mean square root value of the pitching acceleration is reduced by 44.54 %, the mean square root value of the seat acceleration is reduced by 11.31 %, and the improvement of vehicle ride comfort is very obvious.