Robust performance for autonomous intelligent cruise control systems

Abstract

In the last years many efforts for improving safety and comfort in vehicular traffic have been taken. One important aspect of automation components in future traffic patterns is the design of autonomous intelligent cruise control systems. Based on feedback linearization methods, one strategy, for automated vehicle tracking is described comprehensively, which keeps a velocity dependent distance between vehicles in order to provide a constant time-headway. Besides, due to comfort parameters, artificial saturations for the maximum values of the vehicle's speed and acceleration are introduced. However, as a consequence, the problem arises that, as soon as one of these saturations is hit, integral parts of the control algorithms have no effect and, thus, the cruise control system loses its insensitivity to disturbances. Here, a strategy is described in detail, how this loss of robustness can be handled. This strategy, which can be included as an inner loop feedforward controller into most kinds of intelligent cruise control systems, activates itself only if a saturation is hit. Thus, the robustness of the overall system can be guaranteed permanently. Therefore, with respect to cruise control systems, this extension directly contributes to the enhancement of driving comfort and traffic safety.