Coupled longitudinal and lateral control for lane keeping in intelligent transportation systems

Considering the coupling effects between the longitudinal vehicle dynamics and the lateral vehicle dynamics, based on the look-ahead scheme and the constant spacing vehicle following policy, we study the problem of integrated longitudinal and lateral control for lane keeping of vehicles platoon in automated highway systems. Assuming that the lateral displacement offset can be measured with two sensors located at the front bumper and tail bumper, from the coupled longitudinal and lateral dynamic model of vehicle, the look-ahead control system model of vehicles platoon for lane keeping is derived. By applying nonsingular terminal sliding mode technology, the integrated longitudinal and lateral control law for lane keeping is designed. Based on Lyapunov function method, the finite-time convergence property of the system is obtained from the phase-plane analysis. A platoon of six vehicles is used to test the performance of the proposed control law by computer simulation. Simulation results illustrate good track performance for lane keeping and longitudinal following of vehicles in a platoon, and the lateral tracking error is not more than 0.05 m.