Robust lateral controller for 4-wheel steer cars with actuator constraints

In this paper we study a new steering controller for cars equipped with 4-wheel steer-by-wire. The controller commands front and rear steering angles with the objective of tracking reference yaw rate and sideslip signals corresponding to the desired vehicle handling behaviour. The controller compensates for changes in vehicle dynamics with forward speed and incorporates an anti-windup scheme to mitigate the effects of the saturation or failure of the rear steering actuators. We analyse the robust stability and performance of the resulting non-linear control system.