Abstract
Vehicle platooning provides avenues to improve road transportation. However, to safely operate a vehicle platoon, stringent conditions, e.g., string stability, on the closed-loop platoon dynamics must be guaranteed. To meet such platoon control specifications, linear longitudinal vehicle dynamics are usually assumed for the platoon control design and are imposed by using mid-level control systems. However, disturbances and model mismatches can limit the compensation of the nonlinear vehicle dynamics. To systematically impose the linear behaviour to each vehicle in a platoon despite model uncertainties and disturbances, two adaptive solutions are proposed and compared: an adaptive solution for systems in Brunovsky's form and the enhanced model reference adaptive control. Numerical results confirm that both adaptive techniques are effective in imposing the linear dynamics to the longitudinal vehicle motion, also when integrated within a platoon control architecture. The closed-loop platoon performance is assessed via a set of performance indicators for different platoon lengths.