Demonstration of disturbance propagation and amplification in car-following situation for enhancement of vehicle platoon system

Disturbance propagation and string stability of a large vehicle platoon that consists of a part of the traffic flow is closely related to traffic shockwaves and oscillation. In this respect, the concepts of the estimation and prediction of shockwave propagation speeds and congestion should be considered in order to establish a control strategy for safe conditions without collisions even when the congestion is amplified in an unstable string of the large platoon. This means that an advanced approach for a car-following control strategy, which includes a time delay and non-linearity terms, is necessary for the enhancement of Vehicle Platoon Control (VPC) and the system robustness. In this research, we have demonstrated the effect of the disturbance propagation phenomenon on traffic flow stability. The traffic flow shockwave and oscillation are interpreted in terms of both macroscopic and microscopic approaches. We also discuss how the phenomenon affects VPC systems based on the optimal velocity model (OVM), which is an advanced car-following model. In addition, we improve the OVM, which is called the advanced OVM, by including a term for the delay time and by setting up a boundary condition of acceleration in order to enhance the VPC system and to ensure its robustness.