Intelligent time-delay compensation in lateral control of autonomous vehicles using the Smith predictor and LMI techniques

This chapter proposes an enhanced Smith predictor (SM) designed to compensate for a lateral control system affected by an unknown constant time delay. The lateral dynamics are first linearized under specific assumptions, after which a robust fixed-time nonsingular sliding mode controller (FT-NSMC) is developed based on the delay-free model. Although the controller is designed using a delay-free model, it is implemented on a real plant where the actuator is subject to a constant time delay. To address the actuator delay in the steering system, the improved SM (ISM) is incorporated for effective compensation. The critical time delay ensuring system stability is determined through a linear matrix inequality (LMI)–based stability analysis of the delayed system. Simulation results confirm that, without compensation, the control performance deteriorates as the delay increases, leading to overshoots, oscillations, and trajectory deviations. In contrast, with the proposed compensator, tracking accuracy is significantly improved, convergence becomes faster, and the mean-square error (MSE) is reduced by up to 42% under delay conditions. These results demonstrate the effectiveness and robustness of the proposed compensation strategy.