Coordinated throttle and brake fuzzy controller design for vehicle following

The coordinate throttle and brake control is one of the main challenges of vehicle longitudinal control. The main difficulties are due to the complexity and uncertainty of the vehicle dynamics, and the necessity of the switching between throttles and brakes. A hierarchical control system is proposed, in which an upper level controller determines the desired speed/acceleration for the controlled vehicle, while a throttle/brake fuzzy control system is proposed as the lower level controller. To coordinate the two speed actuators, a logic switch is designed. The simulation results show that the automated vehicles equipped with the proposed longitudinal control system have a good speed/spacing tracking capacity, and they are also adaptive to the disturbances of velocity variations and road grades. In addition, the operations of the throttle and the brake are smooth, which means the driving comfort is ensured.