Automatic vehicle following for emergency lane change maneuvers

Abstract

A lane change maneuver is one of the many appropriate responses to an emergency situation. This thesis proposes to design a combined controller for automatic vehicles for an emergency lane change (ELC) maneuver on an Automatic Highway System (AHS). In response to the presence of a stationary or a slowly moving obstacle in the lane or any such emergency, the lead vehicle in the platoon designs an ELC trajectory on-line and broadcasts the trajectory curvature information in real time to its follower through communication. Using the communicated information of its preceding vehicles and the road geometry on-line, the following vehicles track the preceding vehicles' trajectory while maintaining a desired following distance. Control algorithms for the lateral and longitudinal movements of automatic vehicles are developed based on the sliding mode theory for these purposes. In the control algorithms, the desired velocities of the following vehicles, in the lateral and longitudinal directions, are calculated using kinematics relationship between the vehicles. The developed controller is simulated in two different sizes of platoon, a two-vehicle platoon and a six-vehicle platoon, for an ELC maneuver. The performance of the designed vehicle following control laws are tested when the lead vehicle is required to track a circular trajectory and a winding road trajectory in addition to an ELC maneuver. Simulation results for these cases are discussed in this thesis.