Vehicle Speed and Spacing Control Via Coordinated Throttle and Brake Actuation

Abstract This paper presents a combined engine and brake controller for automated highway vehicles based upon the ideas of multiple-surface sliding control. The controller consists of three elements: a task-dependent “upper” sliding controller that incorporates vehicle acceleration as a synthetic input, a switching logic that chooses between brake or throttle control, and individual “lower” sliding controllers for the brake and engine dynamics. The brake controller and switching logic represent substantial improvements over previous designs and produce a closed-loop system that can smoothly alternate between the two control inputs as the trajectory demands. Experimental results show that the vehicle under control is capable of tracking velocity profiles within 0.1 m/s and following a maneuvering lead car at a distance of 2 meters with only 20 centimeter error.