Platoon Tracking Control With Road-Friction Based Spacing Policy for Nonlinear Vehicles

This paper investigates the platoon control problems for a group of nonlinear vehicles, in which the road-friction coefficient between the vehicle and road is taken into consideration. When the road-friction coefficient is small, the platoon safety may be affected with small inter-vehicle spacing headway. Hence, to improve the vehicle platoon safety with various road frictions, a novel spacing policy is developed for the vehicle platoon. This spacing policy is obtained by optimizing a certain safety cost function, which contains both the vehicle positions and the road-friction coefficients. Accordingly, the vehicle platoon would automatically adjust the inter-vehicle spaces to match the road friction. On this basis, a nonlinear vehicle platoon control scheme is proposed such that the vehicles can asymptotically converge to the proposed spacing policy. Particularly, a state observer is developed to approximate the vehicle states, such that only the position measurements can be applied to the control scheme. Moreover, the stability of proposed platoon tracking system is strictly analyzed. In final, numerical simulations are provided to verify the effectiveness and feasibility of proposed approaches.