Hierarchical control for path tracking of autonomous vehicles

This paper studies the path tracking problem for autonomous vehicles in the presence of uncertainties in both tire-road condition and aerodynamic drag. A hierarchical control architecture is adopted, which includes active front wheel steering in combination with low level control of the longitudinal wheel slip. To cope with the unknown and non-uniform road condition parameters appearing in the actuator models, an adaptive law is designed for each wheel, and the wheel longitudinally slipping is required to establish parameter convergence. The stability of the closed-loop system is analyzed by utilizing Lyapunov function approach. Simulation results are included to illustrate the proposed control scheme.