时滞多维轨道不平顺激励的一致白噪声模型

为获得各轮轴处轨道不平顺，用于列车．桥梁振动控制和随机振动分析，研究了轨道不平顺的模拟方法．采用白噪声滤波法生成单轮轴的轨道不平顺；为实现不平顺波长选择，提出了成型滤波器参数的宽频带识别法．为考虑各轮轴间的时延，利用相邻轮轴间的短时滞，构造了基于高阶Pade近似的累次时滞系统．将成型滤波器与时滞系统相结合，得到了以白噪声为输入、列车各轮轴处轨道不平顺为输出的状态方程．算例表明，模拟样本与轨道不平顺目标谱密度相符，且满足各轮轴处轨道不平顺之间的时滞关系．

Uniform White Noise Model for Time-Delay Multi-dimensional Rail Irregularity Excitation

To obtain rail irregularity samples for train-bridge vibration control and stochastic analyses,a simulation method of irregularities at all axles of a train was investigated.Rail irregularity at the first axle was generated by the white noise filtration method.To achieve wavelength selection of rail irregularity,a wideband identification method was proposed for the design of a shape filter.To take time-delay among different axles into account,a step-wised time delay system based on a high order Pade's approximation of the short time-delay between adjacent axles was constructed.By combining the shape filter with the time-delay system,a state equation with uniform white noise as input and irregularities at all axles of a train as output was obtained.A numerical example shows that simulated irregularity samples accord well with the target irregularity power spectral density(PSD) and satisfy the time-delay relation among irregularities at different axles.