BBW(Brake-By-Wire) system is an important technology to meet the requirements of automobile intelligence. BBW system greatly increases the proportion of electronic and electrical components used, so there is a risk of failure. In order to improve the safety and reliability of the BBW system, the concept of functional safety is designed according to the international standard ISO26262. First defines the function of the system safety related items and system application scope, the second use of HAZOP (Hazard and Operability) method for Hazard analysis and risk assessment system (HARA), The vehicle safety integrity level (ASIL) was evaluated according to the Exposure, Severity and Controllability, and the functional safety target of the BBW system was proposed and FTTI(Fault Tolerant Time Interval) was defined. Then, use FMEA(Failure Mode and Effect Analysis) to find the potential cause for the failure of related items, and export the Function Safety Requirement (FSR) of the BBW system accordingly. Finally, a fault injection test was carried out on the designed system. The experimental results show that the FTTI design of the architecture is reasonable, which can timely detect faults and enter the safe state, so as to ensure the safety of drivers. This study has completed the preliminary analysis of the life safety cycle of BBW system development. After analyzing the functional requirements and structure of the linear control dynamic system, HARA is conducted on the system and safety objectives are obtained. According to the safety objective and the preliminary system structure, the concept of functional safety of BBW system is proposed in this paper and distributed to the software and hardware of the system to form a functional safety architecture conforming to ISO26262. Subsequently, the software and hardware of the functional safety architecture of the line control dynamic system are implemented, and the architecture is tested by fault injection. The conceptual design process of the whole system has certain reference value for the subsequent development of the BBW system.
Prof. Dr. Hongyu Zheng, Professor, State Key Laboratory of Automotive Simulation and Control, Jilin University