Comparing Internal Model Control and Sliding-Mode Approaches for Vehicle Yaw Control

In this paper, the problem of vehicle yaw control using a rear active differential is investigated. The proposed control structure employs a reference generator designed to improve vehicle handling, a feedforward contribution that enhances the transient system response, and a feedback controller. Due to system uncertainties and the wide range of operating situations, which are typical of the automotive context, a robust control technique is needed to guarantee system stability. Two different robust feedback controllers, which are based on internal model control and sliding mode methodologies, respectively, are designed, and their performances are compared by means of extensive simulation tests performed using a realistic 14-degree-of-freedom (DOF) model of the considered vehicle. The obtained results show the effectiveness of the proposed control structure with both feedback controllers and highlight their respective benefits and drawbacks. The presented comparative study is a first step to devise a new mixed control strategy that is able to exploit the benefits of both the considered techniques.