Yaw stability control design through a mixed sensitivity approach

In this work a Vehicle Dynamics Control (VDC) system for tracking desired vehicle behavior is developed. A two degrees of freedom control structure is proposed to prevent vehicle skidding during critical maneuvers through the application of differential braking between right and left wheels in order to control yaw motion. The feed-forward filter is a reference generator which compute the desired yaw rate on the basis of the steering angle, while the feedback controller is designed to track the reference as close as possible and to satisfy suitable loop robustness requirements. Mixed-sensitivity minimization techniques are exploited in order to design the loop controller. The performance of the control system is evaluated through Hardware In-the-Loop Simulation (HILS) system both under emergency maneuvers and in non-critical driving conditions, i.e. when the VDC system is not supposed to intervene.