Practical fault-tolerant control to protect steer-by-wire systems against sensor faults

This paper presents a novel practical fault-tolerant control that protects steer-by-wire systems against sensor faults. The proposed strategy aims to reduce sensor redundancy while guaranteeing safety. To reduce redundancy, we design a fault-tolerant control system that has separate controllers - a steering angle feedback controller and a D* feedback controller - in accordance with the impact of the sensor faults exerted on the steer-by-wire system. The sensor necessary for the steering angle feedback is redundant. Conversely, rather than employing redundant sensors on the D* controller, we limit the output of the D* controller to reduce negative impacts that occur right after the sensor faults and isolate the D* control loop after fault detection. Therefore, the yaw rate and lateral acceleration sensors necessary for D* feedback avoid redundancy. Numerical simulations illustrate that the proposed strategy is able to maintain steering functions when the sensor faults occur.