滤波白噪声法的单轮起落架滑跑模型

采用Simulink工具箱和滤波白噪声法生成了各等级道面不平度,按照不平度空域不变,同平整度等级道面振动幅值相同的原则,重点讨论了白噪声生成过程中的参数取值问题。在此基础上考虑起落架缓冲器和轮胎系统的受力情况,建立了升力影响下的单轮起落架滑跑模型,仿真研究了道面平整度和速度耦合作用下机轮动载系数的统计变化规律。计算结果表明:动载系数均值与道面不平度的等级无关;动载系数标准差随滑跑速度的增大而持续增大,但存在与系统固有频率相关的最敏感速度;根据3σ准则确定的动载系数最大值随滑跑速度的增大先增大后减小,速度较小时对道面的动载作用更显著;随着IRI数值的均匀增大,起落架模型由于油液二次阻尼的影响,累计相对位移增速越来越小。

A Quarter Landing Gear Taxiing Model Based on Filtered White Noise Method

Roughness of surface at different grades is generated by adopting SIMULINK toolbox and filtering white noise method . With the space of roughness being unchanged and the vibration amplitude of different level of roughness being equal, parameter selection in the process of generating white noise is discussed emphatically. Then a quarter landing gear taxiing model is established under condition of the influence of lift in consideration of the force of landing gear buffer and tire system. The statistical variation of wheel dynamic load coefficient at different speed and roughness level is simulated and studied. The results shown that the mean value of dynamic load coefficient has nothing to do with the grade of road surface roughness. The standard deviation of dynamic load coefficient increases continuously with the increase of running speed, but there exists the most sensitive speed related to the natural frequency of the system. The maximum value of dynamic load coefficient determined calculated by 3 criterion increases first and then decreases with the increase of running speed. With the uniform increase of IRI value, the cumulative relative displacement growth rate of landing gear model becomes smaller and smaller with the oil nonlinear damping being affected.