车辆磁流变半主动空气悬架模糊滑模控制研究

Research on fuzzy sliding mode control of vehicle magnetorheological semi-active air suspension

为进一步提高车辆行驶过程中的平顺性,提出了一种半主动空气悬架模糊滑模控制策略。对空气悬架系统所用的磁流变阻尼器(Magnetorheological Damper,MRD)进行力学性能试验,利用遗传算法对磁流变阻尼器的改进双曲正切模型进行参数辨识。对空气弹簧建立刚度模型,基于改进双曲正切模型,建立1/4车辆磁流变半主动空气悬架系统模型。针对空气悬架系统的不确定性,建立基于模糊控制的滑模变结构控制策略;通过调整滑模控制的边界层,有效地抑制抖振对控制精度的影响,从而确保了系统的稳定性。以随机路面激励作为输入,分别对被动空气悬架、基于模糊PID控制和基于模糊滑模控制的半主动空气悬架进行仿真分析,结果表明基于模糊滑模控制的半主动空气悬架具有更好的减振性能和乘坐舒适性。

To improve vehicle riding comfort,a fuzzy sliding mode control strategy for semi-active air suspension was proposed.The damping performance test of the Magnetorheological Damper(MRD)used in the air suspension system was carried out.The genetic algorithm was applied to identify parameters of improved hyperbolic tangent model of MRD.Meanwhile,the stiffness model of the air spring was established based on the improved hyperbolic tangent model;then a 1/4 semi-active car air suspension system model equipped with MRD was established.Based on the control of sliding mode variable structure,a fuzzy controller was implemented to establish a Fuzzy Sliding Mode Control(FSMC)strategy,which compensates for the uncertainty of the air suspension system.By adjusting the boundary layer of the sliding mode control,the chattering to control accuracy is effectively suppressed,which ensures the stability of the system.Under the excitation of random road,the comparison between passive suspension and semi-active air suspension applied with fuzzy PID control and fuzzy sliding mode control were theoretically conducted and analyzed.The results show that the proposed control strategy shares a promisingly attenuating effect and riding comfort.