Longitudinal headway control of autonomous vehicles

This paper is concerned with the development of a longitudinal controller for headway regulation of autonomous vehicles on highways. A supervisory hybrid controller is developed to switch between different control actions to implement a smooth intelligent cruise control (ICC) structure. Different decision regions are defined on the phase plane such that human driver actions are emulated as closely as possible. Hysteresis is introduced at the decision boundaries to avoid high frequency switching from one controller to the other. Controllers with constant acceleration (or deceleration), smooth acceleration (or deceleration) and linear state feedback are studied and they are coordinated to efficiently implement ICC. A Kalman observer is employed to filter both the process and the measurement noise in the relative distance and relative velocity reading sensor. The discrete states of operation are modeled for hybrid controller design and the conditions for transitions between those states are indicated. Simulation examples are provided along with some experimental results.