Bulletin of the Polish Academy of Sciences: Technical Sciences

Abstract

In order to improve the safety and comfort of autonomous vehicles passing through the expressway, relevant departments of expressway construction often design and lay consecutive speed control humps (SCHs) with cross-sections of different shapes according to different road conditions, such as the combination of trapezoidal and sinusoidal SCHs. In this paper, we conduct a study about the nonlinear dynamic characteristics of the autonomous vehicle passing through hybrid SCHs. Firstly, a four-degree-of-freedom (4-DOF) nonlinear model of the vehicle suspension and the speed coupling excitation model under hybrid SCHs are established. Then the fourth-fifth order Runge-Kutta method is used to simulate the nonlinear system, and its nonlinear dynamic characteristics are analyzed. The results show that chaotic motion occurs when the vehicle passes through hybrid SCHs, and the speed range of chaotic motion is obtained. Then, a direct variable feedback control method is used to suppress the chaotic vibration of semi-active suspension vehicles, and the effect is verified by simulation experiments. Finally, this paper presents a multi-objective optimization model based on a genetic algorithm (GA) for active suspension vehicles. The optimization model selects the vertical displacement and pitching angle of the vehicle body as the objective function. The research results of this paper can provide information on the ride comfort's optimization for autonomous vehicles passing through hybrid SCHs and on the design of vehicle suspension system.