Two-Stage Lane Keeping Control Algorithm for Lane Sensing Inaccuracy Handling

The Lane Keeping Assist (LKA) system is a safety feature that applies an automatic steering torque to the vehicle steering system to keep the subject vehicle in its lane. Like many other active safety systems, the LKA systems may often experience a performance issue in real road situations. The common LKA performance issues are mainly due to poor quality of the front camera’s curvature data and sudden drops of camera’s detection range. To overcome these issues, this paper proposes a two-stage lane keeping control. In this approach, the LKA has two independent algorithms running with a coordination. In the coordination layer, the secondary lane keeping (LK) control has the authority to override the primary LK control if the primary LK fails to maintain the subject vehicle in the current lane due to the above issues. The key aspect of this system is the accurate timing of the secondary LK’s override over the primary LK. The coordination logic between the primary and the secondary LK control, and smooth transition between the controls are also important performance measures. The determination algorithm of the LK initiation and termination plays a key role in achieving the objectives of LKA fail handling. This paper describes these algorithms as well as the path planning and the steering control algorithms. Several vehicle tests were carried out on curved roads. The results show successful and smooth transition from the primary to the secondary LK layer.