基于线性控制参数的非线性汽车悬架最优控制

Optimal control of nonlinear vehicle suspension based on linear control parameters

为研究非线性汽车悬架的振动控制问题,提出一种基于线性控制参数的最优控制方法。建立了两自由度悬架非线性动力学和数学模型,引入速度和位移线性控制参数,采用平均法导出悬架的主共振幅频响应特性,分析了激励幅值、非线性程度及控制参数的变化对共振幅值的影响。对悬架的稳定性进行分析,在保证振动方程存在稳定解的条件下,得到控制参数的取值范围。以悬架的衰减率和振动能量为目标函数,以控制参数取值范围为约束条件,利用最优化方法得到最优控制参数。研究发现,悬架的非线性振动特性受激励幅值和系统非线性程度的共同影响,在控制过程中速度控制参数起主要作用,当两种控制参数取得最佳值时,悬架共振峰值较无控制参数可衰减88%左右,且悬架的非线性振动特性得到消除。最后利用数值仿真,验证了该方法的有效性。

In order to study the vibration control of nonlinear vehicle suspension,an optimal control method is presented by using control parameters and applied to the control of nonlinear vibration of vehicle suspension system. The nonlinear dynamic and math model of two degree-of-freedom suspension system is built and the linear control parameters of velocity and displacement are applied. The amplitude-frequency response is obtained by averaging method. The following analysis of the effects of excitation amplitude,nonlinear degree and the control parameters on resonance amplitude are studied. The suspension system stability is analyzed,and the range of control parameters is gained on the condition of stable solution of the system. Taking the attenuation rate and vibration energy of suspension system as objective functions and the stable control parameters as constraint conditions,the optimal control parameters are calculated by the optimization method. The results show that the nonlinear vibration characteristic of vehicle suspension is influenced by the amplitude of excitationand the nonlinear degree of the system. The control parameter of velocity plays the main control role. The peak amplitude of suspension vibration can be suppressed about 88% when the optimal values of two control parameters are obtained by comparing with no control parameters,and the nonlinear characteristics can be eliminated. Finally,a simulation example validated the correctness and effectiveness of the results.