A novel handling stability evaluation method for nonlinear vehicle systems based on time-averaged divergence

In the field of automotive nonlinear dynamics, developing an appropriate quantitative metric to evaluate vehicle handling stability is crucial. While the Lyapunov exponent is a potent indicator for analyzing nonlinear vehicle dynamics, its practical application is hampered by its high computational cost and the challenge of solving for high-degree-of-freedom (DOF) systems. Leveraging the established equivalence between the sum of Lyapunov exponents and time-averaged divergence, this paper proposes a computationally efficient and theoretically sound metric for vehicle handling stability. The proposed method is based directly on calculating the time-averaged divergence for nonlinear vehicle systems. The efficacy of the method is demonstrated by investigating the effect of longitudinal velocity on vehicle handling stability. The results indicate that the proposed metric effectively reduces computation time compared to conventional methods without compromising accuracy. Furthermore, because this approach avoids cumbersome matrix orthogonalization, it can be readily extended to higher-DOF or more intricate dynamical systems, demonstrating substantial value for practical engineering applications.