A Distributed Platoon Control Framework for Connected Automated Vehicles in an Urban Traffic Network

In this article, we consider a specific scenario, where multiple connected automated vehicles (CAVs) entering one road link from different upstream links are required to form a platoon first, then cross the junction at the end of the link safely, and fuel economically. Each CAV may experience a reaction-time delay and follow a specific nonlinear car-following model. To address this problem, we design a two-stage distributed platoon control strategy. In the first stage, we present a sufficient condition about the length of a platoon that ensures a subsequent safe junction crossing, upon which a distributed cooperative control protocol is designed and an iteration algorithm is proposed to ensure the fast formation of the platoon in a finite time. Once the platoon is formed, in the second stage, we design a method to estimate the leader vehicle's acceleration adjustment by developing distributed observers that ensure a safe junction crossing of the entire CAV platoon, taking into account follower-vehicle dynamics and an upcoming traffic signal schedule while minimizing the overall platoon fuel consumption. If a platoon has already been formed at the entrance of the link with the appropriate platoon size, then only the second-stage design is needed. Thus, our proposed two-stage CAV link control strategy may potentially become part of a broader fuel-economic solution for the effective management of CAV platoons in a large urban traffic network.