车辆通过连续减速带时的非线性振动特性分析

在7自由度线性系统的基础上考虑悬架弹簧、阻尼和轮胎的非线性,以高速路段的连续减速带作为整车激励,通过对力学模型进行分析并运用拉格朗日法建立系统微分方程。通过MATLAB仿真软件对整车7自由度非线性振动模型的微分方程进行仿真,得到阻尼非线性系数和激励频率的分岔图,发现在一定区域内系统出现复杂的非线性振动,并通过时间历程图、相位图、Poincare截面图和PSP峰值图深入研究系统的周期、拟周期和混沌运动,揭示出阻尼非线性系数和激励频率对系统振动的影响,最后通过拟合即时速度从变速的角度揭示减速车辆通过连续减速带时的振动情况。

Analysis of Nonlinear Vibration Characteristics of Automobiles Passing through Deceleration Zones

Based on 7-DOF linear system, this paper established the mechanical model of whole vehicle which takes the nonlinearity of suspension spring, damping and tire into consideration. The continuous speed humps on the highway pavement was chosen as an excitation. By the analysis of mechanical model and the Lagrange method, differential equation of this system is derived. By using MATLAB, we obtain the bifurcation diagrams of nonlinear damping coefficient and excitation frequency. These two diagrams show that complex nonlinear vibration occurs within a certain range. Time history diagram, phase diagram, Poincare cross section and PSP peak graph are plotted to study the complex nonlinear behavior. Effect of nonlinear damping coefficient and excitation frequency on the system is also studied in this paper. Finally, in terms of varying velocity, vibration of vehicle when passing the continuous speed humps is shown by means of fitting the instantaneous velocity in terms of varying velocity.