ISO26262 application to electric steering development with a focus on Hazard Analysis

The column-drive electric power steering (EPS) system is analyzed using the recommended practices in ISO26262 for the failure mode of “Unintended Steering Assist”. Risk assessment rates this hazard as ASIL-D, i.e. the highest level of risk. A safety goal is applied to the EPS system to avoid and mitigate the risk. Hazard testing results are used to define the “fault tolerant interval”, i.e. the time required to mitigate the fault and revert to a safe state after inception of faults that lead to the hazardous state.