A Robust Disturbance-Rejecting Dual-Layer Adaptive Control of an Autonomous Steer-By-Wire Vehicle Based on Sliding Mode Technique

In this study, a novel dual-layer control structure is designed to enhance the yaw angle stability and lateral displacement tracking of an autonomous vehicle equipped with a Steer-By-Wire (SBW) system. As the upper control, an Adaptive Non-singular Terminal Sliding Mode Control (ANTSMC) scheme is employed to guarantee fast and finite-time convergence of tracking errors of lateral displacement. An Adaptive Sliding Mode Control (ASMC) is then utilized as the lower control for the SBW actuator to precisely track the desired front wheel angle. The common bicycle model, which is a simplified model of an electric car, is considered as the vehicle dynamics of the upper control, while a linear two-degree-of-freedom model is adopted for the SBW dynamics, both subjected to external bounded disturbances representing wind disturbances and the road vibrations. Moreover, to address the problem posed by the unknown upper bound of disturbances and to decrease sudden overshoots, adaptive laws based on the Lyapunov stability criteria have been developed for estimating the switching control policy of the SMC. Simulation results verify the effectiveness of the proposed control framework in regulating the yaw angle and the tracking of lateral displacement of the vehicle. Additionally, comparative analysis with a robust Adaptive Back-Stepping Control (ABSC) strategy reveals that not only does the suggested control scheme have faster settling time, but its ability to reject unknown time-varying disturbances is way better.

کلیدواژه ها:

Adaptive terminal sliding mode control ، SBW system ، Yaw angle stability ، Front wheel angle