  This paper investigates the problem of ecological driving (eco-driving) of
vehicle platoons. To reduce the probability of the platoon avoiding red lights
and increase fuel efficiency, a two-layer control architecture is proposed. The
first layer is in charge of optimizing the leader's long-term motion profile
using the traffic light and road slope information. The long-term planning
model is defined based on the reachability analysis of the platoon to the green
light windows. An event-triggered mechanism is proposed to operate the
long-term planning model. The second layer is the short-term adaptation, in
which the leader attempts to follow the planning motion profile in real time,
while the follower keeps track of the nearest preceding vehicle and the leader,
to preserve the desired inter-vehicular distances. A Newton's method-based
algorithm is implemented to effectively solve both the long-term planning and
short-term adaptation problems. The effectiveness of the proposed formulation
and algorithm is illustrated by the simulations.
