Gain-scheduled LPV/H∞ controller based on direct yaw moment and active steering for vehicle handling improvements

This paper deals with the design of a control scheme that integrates braking and front steering to enhance the vehicle yaw stability and the lateral vehicle dynamics. The proposed VDSC (Vehicle Dynamic Stability Controller) allows control of the yaw rate and obtains good response for the sideslip angle. Besides, this controller takes into account the braking actuator limitations (i.e braking only the rear wheels) and limits the use of the steering actuator only in the linear vehicle handling region (stability region). To reach these objectives, an original parameter dependent LPV controller structure with consistent performances weights is designed. The solution of the problem is obtained within the LMI framework, while warranting H_∞ performances. To prevent tires longitudinal slip due to brake forces generated by the controller, an ABS strategy is included in the control scheme. Computer simulations, carried out on a complex full vehicle model subject to critical driving situations, confirm the effectiveness of the proposed control system and the overall improvements in vehicle handling and stability.