Dynamic Performance of Adaptive Cruise Control Vehicles

Although many different types of Adaptive Cruise Controller (ACC) have been developed to maintain a constant headway between lead and following vehicles, little is known about the dynamic performance of such controllers during cornering and in adverse environmental conditions. There are currently no standard guidelines for the use of ACC systems in such scenarios. Use of the controller in adverse weather or cornering conditions may lead to braking and handling instabilities, or unwanted accelerations being transmitted to the driver in the forms of pitch and roll. These dynamic characteristics are especially important when one considers that ACC systems are being marketed not as safety devices but to aid driver comfort. This paper presents an ACC algorithm that can be tuned to provide desirable dynamic characteristics as well as high-quality kinematic results. The performance of the controller is evaluated using a high-fidelity 9 degree of freedom vehicle model. Firstly the longitudinal performance of the ACC vehicle is examined through a range of straight line simulations with different environmental conditions and levels of acceleration, to investigate the safety of such systems and the pitch accelerations experienced by the driver. The controller is then tested using curved road simulations to examine the effects of ACC on cornering performance as well as the roll accelerations generated.