Technical Paper
A Fail-Operational Assessment for Controllability and Comfortability of Steer-by-Wire Systems
2021-04-06
2021-01-0930
This paper describes a fail-operational evaluation of the controllability and comfortability for the safety architecture development of steer-by-wire (SbW) systems. According to the functional safety requirement, it is demanded that Steer-by-Wire systems shall continue to function and not misbehave after a failure by the intended fail tolerant sub-system. Most recently, developing Steer-by-Wire Systems are well advanced in fail-operational design utilizing the redundant systems, principally using Sensor voting or ECU switching functions. The system can sustainably keep the lateral motion of vehicle even though a failure is detected while driving. During such events, the controllability assessment is used to determine the fault-tolerant time interval (FTTI), including failure detection and the safe state transition time.