Incorporating non-linear tire dynamics into a convex approach to shared steering control

Active safety systems enabled by steer-by-wire technology can share control with a driver, augmenting the driver´s steering commands to avoid collisions and prevent loss of control. The extent to which this can be done is limited by the controller´s ability to anticipate dangerous scenarios in order to appropriately intervene and steer the vehicle to safety. However, the non-linear nature of tire dynamics poses a challenge in predicting and modifying vehicle behavior in real-time. In this paper, online successive linearizations of the future planned vehicle trajectory approximates these non-linear dynamics in a real-time, model predictive controller that shares control with a human driver. Simulation results of aggressive maneuvers demonstrate the usefulness of this approach as well as illustrate interesting interactions between the sometimes competing objectives of vehicle stability and collision avoidance.