Decentralized Platooning System and Integrated Simulator for Cooperative Eco-driving

Abstract

Recent advances in information and communication technology (ICT) have enabled interaction and cooperation between components of the intelligent transport system (ITS). This evolved system is called cooperative-ITS (C-ITS). It promises greater safety, reduced accidents, efficient traffic flow, and fuel consumption reduction. A cooperative eco-driving is a representative system of C-ITS for improving environmental and economic problems of the transportation system. Many studies have investigated the cooperative eco-driving systems for connected vehicles and the test-bed for the testing and evaluation of them. This dissertation proposes a vehicle platooning protocol for connected vehicles (CVs), a service model for cooperative eco-driving, and an integrated simulation test-bed for testing and evaluation of cooperative eco-driving systems. The principal sub-systems of platooning systems for connected and automated vehicles (CAVs) are cooperative adaptive cruise control (CACC) and platoon management systems. Based on vehicle state information received through vehicle-to-vehicle (V2V) communication, the CACC system allows platoon vehicles to maintain a shorter safety distance. In addition, the platoon management system using V2V communications allows vehicles to perform platoon maneuver reliably and accurately. In this dissertation, a CACC system with a variable time headway and a decentralized platoon join-in-middle maneuver protocol with a trajectory planning system considering the V2V communication delay for CAVs are proposed. The platoon join-in-middle maneuver is a challenging research subject as the research must consider the requirement of a more precise management protocol and lateral control for platoon safety and string stability. These CACC systems and protocols were implemented on a simulator for a connected and automated vehicle system, PreScan, and validated using a realistic control system and V2V communication system provided by PreScan. A cooperative eco-driving system is a complex system that requires consideration of the electronic control unit (ECU) and vehicle-to-everything (V2X) communication. To evaluate these complex systems, it is needed to integrate simulators with expertise. Therefore, this dissertation proposes an integrated driving hardware-in-the-loop (IDHIL) simulator for test and evaluation of cooperative eco-driving systems. The IDHIL simulator was implemented by integrating the driving hardware-in-the-loop simulator and a vehicular ad hoc network simulator to develop and evaluate a hybrid control unit and cooperative eco-driving applications for the connected hybrid electric vehicle (CHEV). A cooperative eco-driving speed guidance application was utilized to demonstrate the usefulness of IDHIL simulator. The experimental results showed that the fuel efficiency of CHEV was improved compared to that of normal HEV. These results demonstrated that IDHIL's HEV models, V2X communication, and real-time interaction technologies were correctly implemented and operated.