Linearization and Robust Stability Analysis of Two Degree-of-Freedom Vehicle Dynamics Model

The robust stability evaluation of nonlinear systems has always been a difficult and challenging problem in the field of vehicle dynamics. Some scholars in the field of automobiles have fully studied the stability of vehicles by using the stable region, system bifurcation characteristics and energy in the nonlinear dynamics theory. These evaluation indicators reflect the robust stability of the vehicle system to a certain extent, but they cannot achieve direct objective quantitative evaluation. In this study, we investigate the effect of crosswind interference on the robust stability of the 2-DOF nonlinear dynamics system. The main method is to use Koopman operator theory and dynamic modal decomposition algorithm (DMD) to identify the nonlinear system in the stable region as a linear system, and take the linear system H
∞
norm as the robust stability evaluation index, so as to evaluate the robust stability of the stability region of the nonlinear vehicle dynamic system. This evaluation method provides a dynamic basis for vehicle handling stability evaluation, vehicle stability controller design and vehicle structure parameter optimization, and has a wide range of application scenarios.