Combination of feedforward and feedback H∞ control for speed scheduled vehicle automatic steering

This paper presents speed scheduling of H_∞ controllers for vehicle lateral control. Control synthesis uses a linear vehicle model which includes the yaw and roll motion and is based on loop shaping and robust feedforward H_∞ optimization. The synthesis procedure allows the separate processing of the robust stabilization and the rejection of measured disturbance. The feedforward part processes the road curvature signal and is designed to achieve robust disturbance rejection. The state feedback-observer form of the controllers is used for speed scheduling using robust interpolation. The synthesized controllers are tested for lane keeping maneuvers and disturbance rejection at different speeds and road conditions