Fuel-Efficient En Route Speed Planning and Tracking Control of Truck Platoons

This paper investigates the problem of speed planning and tracking control of a platoon of trucks on highways. We present a two-layered hierarchical framework for truck platoon coordination: a speed planning layer for en route speed profile calculation and a control layer for vehicle speed tracking. The speed planning algorithm is derived with regard to an average vehicle based on a combined fuel-time cost and receding dynamic programming. The idea of using an average vehicle instead of the platoon leader for speed planning makes the resulting speed profile more fuel-efficient for platoons comprised of vehicles differing in weight and size. The vehicle controller, a discrete time back-stepping control law, is designed on the basis of a nonlinear vehicle model considering road slope and heterogeneity of the vehicles. What makes the control algorithm more interesting is that it is strengthened by a novel string stability criterion. The effectiveness of the method is demonstrated by both numerical simulations and experiments with laboratory-scale Arduino cars.