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.