基于增量谐波平衡法的汽车转向系非线性动力学特性研究

Nonlinear dynamics of automobile steering using incremental harmonic balance method

汽车转向系的振动会导致车辆行驶不稳定,从而引发车祸。因此在考虑间隙与干摩擦非线性因素的基础上,建立了独立悬架汽车转向系振动的四自由度非线性动力学模型,对间隙分段函数采用了多项式曲线拟合;应用增量谐波平衡法和插值技术求解了多自由度强迫型非线性振动系统解的基波与超谐波成分,对其极限环幅值进行了预测,并与四阶RK法所计算的结果进行对比分析,证明了该方法的快速性与准确性;在此基础上分别分析了系统的幅频与相频特性,间隙与干摩擦因素对系统振动特性的影响;研究结果对如何消除转向系振动与其振动的非线性控制具有理论指导意义。

Unstable dynamic phenomenon maybe occur due to the oscillation of automotive steering when vehicle is running.This can bring about traffic accident.Nonlinear dynamic equations with 4 degrees of freedom for independent automotive steering with suspension were established.Here the factors of clearance and coulomb friction were taken into account.Using polynomial curve fitting method,clearance subsection function is described.The incremental harmonic balance method and interpolation technique which were applied to this study forecasted the amplitude of limit cycle by multi-harmonic analysis.Simultaneously,fundamental harmonic and super harmonic of the system can be obtained.The IHB method gave results with short time and high accuracy compared with numerical results given by 4 orders RK method.Amplitude and phase characteristics,influence of coulomb friction and clearance that were calculated can help us to direct nonlinear dynamic control of steering system and avoid its vibration.