Saturation-Tolerant Adaptive Prescribed Performance Control of Multitasking Steer-by-Wire System With Hardware Experiments

To address the unresolved challenge of angle tracking performance degradation and potential instability in steer-by-wire systems under actuator input saturation and faults, this paper proposes a novel saturation-tolerant adaptive prescribed performance tracking control scheme. The approach uniquely integrates event-triggered mechanisms and adaptive auxiliary systems into a unified finite-time prescribed performance control framework, enabling adaptive compensation for saturation-induced errors and accommodating multi-task steering characteristics of “action-wait” intermittent control. Importantly, the inherent initial condition constraints and potential singularity issues found in conventional prescribed performance control are eliminated, ensuring tracking errors remain within the performance envelope while enhancing the system’s transient response. To simultaneously address time-varying disturbances and unmeasurable states, a new high-order finite-time extended state observer is developed, removing the need to design two separate observers. In addition, an adaptive angle tracking controller with disturbance compensation is constructed using the dynamic surface control technique, where a new finite-time convergent nonlinear filter is introduced to avoid cumbersome computations and error accumulation. Finally, hardware experiments verify the superiority and real-time capability of the proposed method, with a computation time of 0.24 ms confirming its suitability for embedded automotive applications.