准零刚度空气悬架系统建模与动态特性研究

Modeling and dynamic characteristic analysis of a quasi-zero stiffness pneumatic suspension system

为提高商用车辆行驶平顺性,提出一种适用于商用车的准零刚度空气悬架系统。首先,考虑到不同载质量对静位移的影响,正刚度机构采用了空气弹簧,通过充放气使系统处于预定平衡位置;负刚度机构采用双作用气动执行器,通过内部高压气体抵消部分弹簧力,以实现动刚度的减小;在分析系统刚度特性时,将空气弹簧内部气体变化看作为等温绝热过程,利用气体状态方程推算出空气弹簧刚度公式,代入系统恢复力得出系统刚度表达式,利用其表达式对系统进行参数设计并建立悬架1/4模型,分析准零刚度空气悬架系统与传统空气悬架系统在垂直方向上的运动特性差异;最后,进行相应试验并验证系统的有效性。结果表明:提出的悬架系统使车身垂向加速度均方根值减小了15%,垂向动行程增加了不到4%。该系统的提出也为悬架提升减振性能提供了新的思路。

To improve the ride comfort of commercial vehicles,a quasi-zero stiffness pneumatic suspension system for commercial vehicles was proposed in this paper.First,air spring was adopted to realize the positive stiffness for variable load.By charging and venting of the air spring,the system was stabilized at the predetermined equilibrium position.The negative stiffness system adopted double-acting pneumatic actuators to reduce the dynamic stiffness.Secondly,when analyzing the system stiffness characteristics,the changing progress of gas inside the air spring was regarded as an isothermal adiabatic process and air spring's stiffness was gained by substituting the equation of gas state.Then,the parameters of the system were designed by calculating the system stiffness and the one-quarter suspension model was built to analyze the dynamic characteristic.Finally,the validity of the system was verified by experiments.The results show that the proposed suspension system reduces the root-mean-square value of vertical acceleration by 15%and increases the vertical dynamic travel by less than 4%.