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为了提升车辆的乘坐舒适性,降低在恶劣道路环境下悬架撞击限位块的概率,建立七自由度非线性主动悬架模型,采用滤波技术对主动悬架控制器进行优化研究。构建线性滤波Backstepping主动悬架控制器,对其进行零动态特性分析,以保证系统的稳定性。针对此类控制器不能调节低通带宽从而无法实现根据车辆运行工况对控制目标进行调整的缺陷,构建滤波参数可调的非线性滤波控制器,通过对低通范围的自适应调节,实现对悬架动挠度及车身加速度均衡控制。通过对正弦路面和随机路面进行仿真分析,对比研究自适应滤波、线性滤波主动悬架及被动悬架加速度参数及右前车轮悬架动挠度,分析其对车辆舒适性和操纵稳定性的影响。研究结果表明:在小激励时基于线性滤波及非线性滤波的主动悬架减振效果相似,相比被动悬架可以将加速度参数降低80%以上;在大激励极限工况时,线性滤波控制器对加速度参数的改善更加显著,而非线性滤波控制器降低了悬架动挠度。对比车轮动位移参数可知,主动悬架2种滤波器皆有效降低了轮胎脱离路面的概率。基于自适应滤波的非线性Backstepping控制是提升车辆舒适性和操纵稳定性的有效方法。
In order to improve the ride comfort of the vehicle and reduce the probability of the suspension impacting the stopper in the bad road environment, a seven-DOF nonlinear active suspension model is established and the active suspension controller is optimized by using the filtering technology. Constructs a Linear Filter Backstepping Active Suspension Controller and analyzes its zero dynamic characteristics to ensure the stability of the system. Aiming at the defect that the controller can not adjust the low pass bandwidth and can not adjust the control target according to the operating conditions of the vehicle, a nonlinear filter controller with adjustable filter parameters is constructed. By adjusting the low pass range adaptively, Suspension dynamic flexibility and body acceleration balance control. Through the simulation analysis of the sinusoidal pavement and the random pavement, the adaptive filtering, acceleration of linear active suspension and passive suspension and the dynamic deflection of the right front wheel suspension are compared, and the impact on the vehicle comfort and handling stability is analyzed. The results show that the vibration damping of the active suspension based on the linear filtering and the nonlinear filtering is similar at low excitation, and the acceleration parameter can be reduced by more than 80% compared with the passive suspension. Under the large excitation limit condition, the linear filtering controller The improvement of acceleration parameters is more significant, while the nonlinear filter controller reduces the suspension dynamic deflection. Comparing the dynamic displacement parameters of the wheel shows that the active suspension two kinds of filters are effective in reducing the probability of the tire off the road. Nonlinear Backstepping control based on adaptive filtering is an effective method to enhance vehicle comfort and steering stability.