Fault Tolerant Control of 4WIS Based on Failure Event Triggering and Self-Reconstruction Model

When traditional steer by wire (SBW) faults, vehicle loss of control can lead to serious safety accidents. The four-wheel independent steering system (4WIS) still has steering control capability in the fault situation. However, current research on four-wheel steering system (4WS) fault-tolerant control has overlooked the changes in wheel force after failure fault, resulting in severe shaking and frequent safety accidents. Therefore, this article proposes a 4WIS fault-tolerant control strategy based on failure event triggering and model self-reconstruction. First, an extended event-triggering failure diagnosis strategy is proposed to improve diagnostic reliability and determine fault modes. Next, a model self-reconstruction method considering fault state prediction is designed to accurately predict the lateral and longitudinal forces of the faulty wheel, and then achieve model self-reconstruction based on the fault mode. Then, a fast contraction self-reconstruction model predictive control strategy based on expansive event triggering (EETFSR-MPC) is designed to construct error shrinkage trajectories and ensure the stability of vehicles in trajectory tracking. Finally, simulation analysis was conducted using Carsim/Simulink, and hardware-in-the-loop (HIL) experiments were conducted on the 4WIS testing platform. Simulation analysis, experimental results, and numerical analysis validate the fault-tolerant control strategy proposed in this article.