Hazard Identification Method for Safety of the Intended Functionality Based on Finite State Machine

Abstract:

Aimed at the dependence of hazards of the autonomous driving system （ADS） and scenarios， a method for identifying hazards of the safety of the intended functionality （SOTIF） at the vehicle level is proposed based on the finite state machine （FSM）. First， the elements constituting hazardous events are specified. Then the FSM is adopted to abstract the ADS in combination with vehicle states and the operational environment. Finally， by identifying the conflicts between vehicle states and the operational environment， hazardous events of the ADS related to the SOTIF are systematically identified， which overcomes the overdependence on expert knowledge. The proposed method is applied to identify hazardous events on an SAE L3 autonomous vehicle to verify its effectiveness. The results show that compared with the system theoretic process analysis （STPA） method， the FSM model contains more detailed and systematic environmental information and the elements constituting the hazardous events are directly provided by the FSM model， which supports systematic identification of hazardous events.

Key words:autonomous driving;safety of the intended functionality(SOTIF);functional safety;finite state machine;hazardous events