Non-linear steering control for limit handling conditions using preview path curvature

Abstract

Path-following steering control has many applications in autonomous driving, which may one day lead to cars running on autopilot. The developed controller addresses the path-following task by the required path curvature to reach a single preview point ahead of the vehicle as input to the controller. A pre-defined non-linear map of steering angle vs. curvature and vehicle speed is used to calculate the required steering angle. Calibration of the controller is done by performing a simple steady-state circle manoeuvre. The controller is evaluated using both simulations and experiments. Excellent path-following performance is achieved all the way up to the limit of adhesion. The actuation is smooth and the error rarely exceeds 1 m even at lateral acceleration levels of up to 10 m/s2.