Steering angle tracking control of steer-by-wire system with prescribed performance under primary sensor failure

A key challenge of steer-by-wire systems is that they require a desired steering angle to be followed accurately. In this paper, a steering tracking control method with prescribed performance under sensor failure is proposed to enhance the tracking performance and reliability of steering execution. To mitigate the adverse effect of the coupled steering resistance moment and estimate the unmeasured state variable, a rack force estimator based on an extended disturbance observer is developed. By designing a new preset time performance function, the tracking error is guaranteed to converge to a predefined quantitative constraint within a preset time. Notably, the convergence time and the tracking accuracy can be set arbitrarily, independent of system parameters and initial states. The present study presents a fast fault detection method and formulated corresponding fault-tolerant strategies, aiming to ensure the continued proper functioning of steering tracking control in the event of sensor failures. Through verification and comparison with hardware-in-the-loop experiments, the proposed method achieves high transient and high-precision tracking performance even under aggressive steering and sensor failure conditions, while being easily embedded applied in engineering practice.