Fault Diagnosis and Fault Tolerance Degradation Control Based on Fuzzy Decision for RSAS of Redundant Braking System

Redundant braking system (RBS) is an important part of intelligent vehicle safety. Accurate and stable steering wheel angle is the key signal to realize vehicle stability control (VSC). Hence, in order to improve the reliability of the angle signal in the RBS, a redundant steering wheel angle sensor (RSAS) is developed and designed, and a fault diagnosis and fault tolerance degradation control (FDFTDC) strategy based on fuzzy decision is proposed in combination with the steering system. The RSAS consists of a main gear connected to the steering wheel column, and the two pinion pairs are redundant to each other. Based on RSAS, a steering wheel observer is introduced to establish steering wheel angle fault diagnosis and fault-tolerant control strategy. Finally, it is applied to the stability of the braking system. The results show that FDFDTC can effectively diagnose and control the steering wheel Angle signal, improve the safety redundancy of the system, and effectively improve the robustness of the RBS in the vehicle stability. When one of the RSAS fails, the MSE is 0.0616, with the same deviation as normal. In the RBS system, when all RSAS fail, the MSE is 0.0867, which can still guarantee the function of the system.