Integrating Vehicle Slip and Yaw in Overarching Multi-Tiered Vehicle Steering Control to Balance Path Following Accuracy, Gracefulness, and Safety

Balancing path-following accuracy and error convergence with graceful motion in steering control is challenging due to the competing nature of these requirements, especially across a range of operating speeds and conditions. This paper demonstrates that an integrated, multi-tiered steering controller considering slip in kinematic control, dynamic control, and steering actuator rate commands achieves accurate and graceful path following. Kinematic and dynamic models are adapted to include slip. A path-following kinematic controller is then derived using a continuous, time-varying, and speed-based variable-structure controller (VSC) to balance safe and graceful motion with robust error convergence. Yaw rate commands from the kinematic controller are nested in a backstepping slip–yaw dynamic tracking controller to generate steering rate commands. A high-gain observer (HGO) estimates the sideslip and yaw rate, which are used in sensor-based output feedback control. Stability analysis of the output feedback controller is provided, and peaking is resolved. The work focuses on lateral control alone so that the steering controller can be combined with other speed controllers. Field results demonstrate gracefulness and accuracy along complex paths in variable terrain, in different weather conditions, and with perturbations.