  This paper presents a distributed model predictive control (DMPC) algorithm
for a heterogeneous platoon using arbitrary communication topologies, provided
each vehicle can communicate with a preceding vehicle in the platoon. The
proposed DMPC algorithm can accommodate any spacing policy that is affine in a
vehicle's velocity, which includes constant distance or constant time headway
spacing policies. By analyzing the total cost for the entire platoon, a
sufficient condition is derived to ensure platoon asymptotic stability.
Simulation experiments with a platoon of 50 vehicles and hardware experiments
with a platoon of four 1/10th-scale vehicles validate the algorithm and compare
performance under different spacing policies and communication topologies.
