Formation Control of Connected Vehicles: from cooperative to mixed human-driven/automated platoons

Recent years have seen the rapid development of connected vehicles research and technology. A typical example is the Cooperative Adaptive Cruise Control technology, where on-board sensors and inter-vehicle communication aim to group automated vehicles into platoons. Unfortunately, despite the promises of enhancing efficiency of traffic flow, the control algorithms embedded in connected vehicles are still unable to deal effectively with vehicle uncertainty and interaction with human-driven vehicles. This thesis considers control problems arising from such situations, and proposes new methodologies for platoons with automated vehicles or with mixed automated/human-driven vehicles.

We start by studying an algebraic loop problem arising in merging scenarios with bidirectional (cyclic) communication among cooperative vehicles, and the problem of having heterogeneous engine limits in the platoon. We then turn our attention to the interaction between automated and human-driven vehicles in platooning scenarios. To study this interaction, the literature has proposed the notion of head-to-tail string stability. We introduce a theoretical framework for the problem of head-to-tail string stability of mixed platoons. Finally, we propose a reachability approach to study disturbance and safety propagation in mixed platoons. We look at the behaviour of the leading vehicle as a unit-energy disturbance and we study how this energy propagates. This analysis can be extended to a design setting, with the purpose of designing a control strategy for the automated vehicle that optimizes the propagation of energy along the platoon.