Adaptive Steering Feel Control for Steer‐By‐Wire Vehicles Under Uncertainties and Time Delay

ABSTRACT In steer‐by‐wire (SBW) vehicles, the steering feel feedback system is essential for providing realistic torque feedback to the driver. However, its performance is often degraded by the simultaneous presence of system uncertainties and time‐varying delays caused by communication and computation. While existing studies have addressed either uncertainty or delay separately, their combined effect remains underexplored. This article proposes a novel integrated control framework that simultaneously handles both challenges. First, a barrier function‐based adaptive super‐twisting sliding mode control (STSMC) is employed to ensure robustness against system uncertainties. To further mitigate communication‐induced delays, a relative threshold event‐triggered mechanism is introduced, which significantly reduces unnecessary data transmission compared with conventional fixed‐threshold methods. Second, to compensate for residual time‐varying delays that cannot be eliminated by event‐triggering alone, a Grey‐Markov time delay prediction model is developed. This model combines grey system theory for trend extraction and Markov chains for stochastic fluctuation correction, enabling accurate real‐time delay estimation. The predicted delay is then integrated into a fuzzy adaptive Smith predictor, which dynamically adjusts compensation parameters to enhance system robustness and response speed. Simulation results under high‐speed and low‐speed steering conditions demonstrate that the proposed strategy reduces the maximum absolute error by more than 50% and the root mean square error by more than 10% compared with conventional Markov‐based methods, while also reducing communication frequency.