运动副间隙对汽车摆振系统非线性动力学行为影响分析

在前期研究中发现运动副间隙对机构的动力学响应影响显著，因此做出转向系统中的间隙也会对转向摆振系统的响应产生重要影响的推断。为此，将转向梯形机构简化为一个连杆机构，并就机构中运动副间隙对转向系统摆振的影响进行了分析。借助拉格朗日方程建立考虑转向机构运动副间隙的6自由度转向系统摆振动力学模型，基于该摆振模型，应用四阶龙格－库塔法对间隙参数发生变化时摆振系统的响应进行仿真分析。通过仿真分析结果发现：转向机构运动副间隙是诱发转向轮摆振系统混沌运动的重要因素，在摆振系统建模过程中应予以充分考虑；随着运动副间隙增大，转向摆振系统会由周期运动状态经过拟周期运动状态逐渐进入混沌状态，造成摆振运动加剧。相关结论可为转向系统摆振的有效控制奠定理论基础。

Influence Analysis of Movement Pair Clearance on Nonlinear Dynamic Behavior of Vehicle Shimmy System

Previous research showed that the clearance of the movement pair can considerably influence the dynamic response of the mechanism. As a result, it can be deduced that the clearance of the steering mechanism also can have great influences on the steering wheel shimmy system. Therefore, the steering trapezium is simplified as a linkage mechanism, and the influences of the clearance on the steering wheel shimmy system are discussed. The 6-DOF dynamic model of steering wheel shimmy with consideration of movement pair clearance of steering mechanism is established with Lagrange equations. Based on this model, examples with different clearance of the movement pair are analyzed with 4-order Runge-Kutta method in order to evaluate the effect of the clearance on the dynamic behavior of the vehicle shimmy system. Simulation results show that the clearance is an important factor in inducing the chaotic motion of the vehicle shimmy system, so it should be considered adequately in the modeling process of shimmy system. With the increase of the clearance, the system experiences the variations from periodic motion, to quasi-periodic motion, and further to chaos state. The correlative conclusions can provide theoretical basis for effective control of the steering wheel shimmy.