基于微分几何理论的汽车半主动悬架非线性振动控制

Nonlinear control of automotive semi-active suspensions based on differential geometry theory

针对汽车悬架系统的非线性特性,采用1／4汽车二自由度悬架模型分析半主动悬架控制。应用微分几何理论得到输出-干扰解耦方法,再经适当的坐标变换将该模型由非线性系统简化成一线性系统,并对此系统进行最优控制,然后通过非线性状态反馈实现对原系统的半主动控制。与被动悬架的仿真结果进行了比较,表明这种针对具有非线性特征的半主动悬架的非线性控制方法是可行的。通过功率谱分析,控制后系统的能量比被动悬架更趋于平均,悬架动态性能更稳定。

Based on the analysis of nonlinear characteristics of automotive suspension system, a quarter-automotive suspension model is adopted in this paper. In order to study and obtain a control strategy for nonlinear vibration system of an automotive semi-active suspension, an output-perturbation-uncoupled method is applied with differential geometry theory. The nonlinear model of the semi-active suspension is transferred to be a simple linear system by an appropriate coordinate transformation. Then, the optimal control scheme is applied to the simple system and is carried out to control the original system through a nonlinear state feedback. Finally, compared with an active suspension and a conventional passive suspension, respectively, the simulation results indicate that the nonlinear control strategy is more feasible in allusion to the existing elements of semi-active suspensions with nonlinear characteristics. So this control strategy can not only attain an excellent effect on weakening vehicle vibration and disturbance, but also coincide with the practical condition.