Constant Partial Frequency and Constant Height Design of Nonlinear Commercial Vehicle Bionic Suspensions

Abstract

Aiming at the problems of poor vehicle ride comfort during variable sprung mass of commercial vehicle suspensions based on full-load design, a design scheme of constant partial frequency and constant height was proposed based on double diamond-shaped kangaroo leg suspensions(bionic suspension). The scheme was researched, analyzed and evaluated to improve the ride comfort of commercial vehicles. Through the analysis of statics characteristics, the elastic characteristics and stiffness characteristics of the bionic suspensions were obtained, and the constant partial frequency and constant height design was carried out. It is found that the bionic suspension has ideal nonlinear elastic characteristics and stiffness characteristics. Compared with the linear suspensions, it has more dynamic capacity and strong anti-breakthrough ability. The initial angle and stiffness ratio of the suspensions have important impacts on the characteristics and stroke range. By adjusting the initial angle of the bionic suspensions, the constant partial frequency and constant height design maybe realized for different sprung mass, which shows the proposed scheme is feasible. The simulation analysis results show that under different road grades(B, C, D) and different vehicle speeds(40~100 km/h), the body acceleration root mean square value is significantly reduced compared with before design, and the ride comfort is effectively improved after the constant partial frequency and constant height design for the commercial vehicle bionic suspensions. After the design of constant partial frequency and constant height, under different road conditions, the no-load and half-load vertical acceleration root mean square values of the bionic suspension experimental test model are decreased by 20.6%~28.3% and 12.1%~20.4% respectively compare with before design, which verified the correctness and effectiveness of the design schemes of constant height and constant partial frequency.