Shimmy analysis of steering system with independent suspension based on coupled feedback model

Abstract

Abstract Shimmy of steering system causes the snaking and deteriorates the handling stability and safety of vehicles, which has not been solved effectively for the ambiguity of shimmy characteristic. In order to uncover the mechanism of shimmy, a 5-DOF dynamic model of the steering system with independent suspension is established, and the coupled feedback model of the steering system is further obtained based on the dynamic model. Then the frequency characteristics of feedback are analysed, and the work and damping energy dissipation of each feedback link in a unit period are calculated. Based on the range of natural frequency and unit periodic energy of steering system, the range of wheel shimmy frequency and velocity interval is determined. The analysis results show that the shimmy frequency is the first natural frequency of steering system. The amplitude of wheel shimmy is calculated based on energy conservation, and the energy transfer of steering system is elaborated. The mechanism of shimmy was uncovered based on the energy transfer of coupled feedback system. The theoretical analysis was verified by numerical simulation. The results provide theoretical support for the mechanism research and active control of shimmy.