Longitudinal control of an autonomous vehicle through a hybrid fuzzy/classical controller

Abstract

This research on the longitudinal control of a motor vehicle was carried out as part of the Autonomous Intelligent Cruise Control (AICC) project, which is itself part of the PROMETHEUS European Community program. It has two objectives: a speed regulation-the driver sets a cruising speed, the vehicle reaches that speed and keeps it; a distance control-when the AICC vehicle detects a target vehicle, it decides whether it is necessary to modify the actuator instructions so as to place itself at a safe distance behind the vehicle in front. These two operating modes are permanently active and must satisfy subjective criteria of comfort while ensuring a high robustness in control. These constraints are one reason why we had a hybrid approach in the conception of the regulator. Indeed, a classic type of control (by internal model) ensures a deceleration/acceleration regulation of the vehicle; the deceleration/acceleration instruction being generated by a controller based on fuzzy logic methods. This original hybrid control guarantees the robustness criterion even if there is a variation of the structural parameters such as mass, and if there are model errors as well. It also enables the driver to personalize the running of his vehicle by selecting a driving style ("comfortable", "sportslike", ...). With the controller thus conceived we obtain quite satisfactory results within the desired limits of use.<>