雨刮器非线性摩擦振动的稳定性与分岔特性

针对雨刮器建立2自由度非线性摩擦振动动力学模型,基于复模态理论计算复特征值并进行稳定性及其对刮刷速度的依赖性分析;通过数值计算分析摩擦振动对刮刷速度的分岔特性,并利用相轨迹、庞加莱映射、频谱特性分析不同刮刷速度下的非线性振动现象.研究发现:摩擦-速度特性的负斜率是导致系统不稳定的根本原因,增大刮刷速度有利于提高系统的稳定性;在高、低刮速区,随着刮刷速度的下降,系统振动形态遵循周期→准周期→混沌的演化规律,并会伴随显著的粘滑振动;仅高速区的周期振动和非振动条件下,刮刷时无附加的粘滑振动.

Stability and Bifurcation of Nonlinear Frictional Oscillation of Automotive Wiper System

In this study, a 2 DOF nonlinear friction induced vibration dynamic model of the automotive wiper system was established, and complex eigenvalues were calculated based on the complex modal theory, and system instability and its dependence on wiping velocity were analyzed. Bifurcation of friction induced vibration with respect to wiping velocity was studied by means of numerical methods, in which phase trajectoriés, Poincare map, and frequency spectrum were adopted to analyze the nonlinear vibration under various wiping velocities. The results indicated that the negative slope characteristic of friction-velocity curve was the root cause for the system instability, and increasing the wiping velocity benefited the system stability. As the wiping velocity decreased, the vibrations changed from periodic to quasi-periodic motion and then to chaos, in both high and low velocity ranges. It was also found that there accompanied prominent phenomenon of stick-slip vibrations, which vanished in the higher velocity range, where only periodic motion and non-oscillatory motion occurred.