H<inf>∞</inf> control with look-ahead for lane keeping in autonomous vehicles

In this paper a path tracking control for an autonomous vehicle is developed using the H ∞ technique. The lateral control problem is reformulated as the control of two variables: the lateral error and the derivative of the look-ahead error, defined as the distance between a virtual point on the vehicle longitudinal axis in front of the CoG and the reference trajectory. This approach is based on the fact that while driving on a constant curvature trajectory the derivative of the look-ahead error must be 0. The effectiveness of the proposed control strategy is demonstrated with experiments on a 2013 Dodge Dart equipped with throttle, brake and steer-by-wire system and in simulation on CarSim. A model of the vehicle is identified, validated by experimental tests and used to tune the simulator. The steering actuator dynamics is also taken into account since it significantly affects the dynamics of the total system.