Model Establishment and Parameter Analysis on Shimmy of Electric Vehicle with Independent Suspensions

In order to study the shimmy problem of the electric vehicle with independent suspensions, a 5 DoF model is established using the Lagrange Equation. Gyroscopic moment and tyre nonlinearity are both considered, and tyre-road constraint equations are derived on the non-slip assumption. Stability charts are conducted with the linearized model, while numerical simulation is also made so that these two methods can verify each other. The results show that bifurcation occurs at certain vehicle forward speed. Suspension structural parameters, such as caster angle, affect wheel shimmy. Furthermore, the presented model enables the analysis of any parameters in the system, and as an example, the influence of dampings on shimmy is investigated.