An emergency braking controller based on extremum seeking with experimental implementation

Abstract

An extremum seeking scheme is developed for maximizing the longitudinal tire forces of the road vehicles during emergency braking situations. If the road condition is known, then a conventional braking controller could generate required braking moment to track the slip set point which belongs to that road condition. However, estimating the road condition is not an easy task and it brings additional computation effort. Rather than that, a self optimization algorithm is presented in this paper without relying on road condition estimation. The developed controller searches optimum operation point for getting maximum friction force. Computer simulations show the effectiveness of the self optimization routine. To validate the real time applicability of the algorithm, an electromechanical braking test system is used for the experiments. Due to the limited measurements from the experimental system, force and moment observers are designed to calculate necessary control inputs for maximizing the friction potential, i.e. the braking force. Via the experimental study, it has been shown that the developed self optimizing controller is fast, accurate, and operable on a real braking system.