Design of Adaptive Yaw Rate Control System of a Car

In this paper we propose a design method of adaptive yaw rate control system of a new-type automobile car having electronically controlled rear wheel steering mechanism.First, the spectrum density of steering wheel angle and yaw rate was measured on popular roads and cut-off frequency of the control filter could be determined between 1 to 3Hz. Next, parameters of the car model were identified by the hybrid-type adaptive method using measured data of vehicle velocity, steering wheel angle and yaw rate. The results were shown to be acceptable based upon the comparison between time responses, where the measured data of steering wheel angle is used as input, and the Bode diagrams of nominal and estimated systems.The desirable output response of the closed-loop system was obtained by a simulation using control parameters, which were used to the nominal system, calculated from the identified ones. The results indicate that the proposed method is useful to design actual control systems of a car.