车辆四轮相关路面非平稳随机输入通用时频模型

GENERAL NONSTATIONARY RANDOM INPUT MODEL OF ROAD SURFACE WITY FOUR WHEELS CORRELATED

车辆非匀速行驶时路面的随机输入模型是汽车非平稳动力学分析研究的重要基础。首先应用等效协方差方法建立了单轮随机输入非平稳时域模型。根据时间-空间一、二阶微分关系,成功地解决了前后轮变时差相关的问题,并由各向同性假设直接得到了与车辆轮距有关的左右轮相干函数,无需实测相干函数,因此适合各种车辆。本文还应用Wigner-Ville谱分析了路面非平稳随机输入的瞬时功率谱。分析表明Wigner-Ville谱很好地反映了频率特征和路面波形特征。

Equivalent covariance method was used to establish the single wheel model with nonstationary random input, then according to the relationship between first and second order differentials, the correlation with variable time lag between front and rear wheels was resolved. Based on the assumption of isotropy, the coherent function between left and right wheels was directly deduced without measurement. The model is applicable to various kinds of vehicles, and can be easily used in calculation. The Wigner-Ville spectrum was also applied to analyse the instantaneous spectrum of road random inputs for reflecting the frequency and wave shape characteristics.