Abstract:

Designed a functional safety concept for a steer-by-wire (SBW) system, which is highly regarded for future intelligent vehicles, based on the “road vehicle functional safety standard of the ISO 26262” by the International Organization for Standardization (ISO) to improve the safety and reliability of the SBW system.
Analyzed some possible situations of road vehicle for the requirements of reliability according to the analysing to the system functional requirements and architectures. Identified some possible hazards and evaluated the automotive safety integration levels (ASILs) using a rule-set method. Proposed two safety goals that the system should avoid unintended steering torque beyond function limits and should avoid steering function loss in high speed. A functional safety concept was designed and then distributed into architecture elements to detect the faults on time and to switch to backup architectures after faults. The results of test show that the functional safety architectures of the SBW system improve the reliability effectively and ensure driver’s safety by entering safety state when break down.

Key words: intelligent vehicles, steer-by-wire (SBW), road vehicles, functional safety, standard ISO 26262, automotive safety integration levels (ASILs)