Robust adaptive non-singular fast terminal sliding-mode lateral control for an uncertain ego vehicle at the lane-change maneuver subjected to abrupt change

Abstract

This paper investigates a new approach to deal with the path-tracking for an uncertain autonomous ground vehicle (AGV) exposed to the unknown external disturbances caused by abrupt changes in the road bank angle. A robust adaptive non-singular fast terminal sliding mode control (RANFTSMC) is designed for the lane change maneuver (LCM) lateral control. Initially, a reference LCM path is planned by a recent procedure. Then, assuming that the upper bound of unknown external disturbances and uncertainties is known, a robust steering controller is implemented via non-singular fast terminal sliding mode control (NFTSMC) to ensure the vehicle lateral stability. However, the upper limit of the vehicle uncertainties and perturbations is unknown in real-world driving situations, therefore, an adaptive tuning law is developed to estimate this unknown upper bound. As long as the efficiency of the controller depends on their parameters, a meta-heuristic optimization algorithm is employed to deliver the controller optimal settings. The effectiveness of the proposed RANFTSMC is proven with theoretical illustrations and numerical simulation results. The offered steering controller maintains the lateral stability even in severe conditions where the vehicle longitudinal speed is up to 120 km/h. In this connection, the suggested strategy is compared with the higher-order sliding mode controller (HOSMC) and conventional sliding mode controller (SMC).