A Research on SOTIF of LKA based on STPA*

Abstract

Because of the safety risks caused by functional insufficiencies and performance limitations for automated vehicle, the Safety of The Intended Function (SOTIF) of the Lane Keep Assistance (LKA) system is studied based on the System-Theoretic Process Analysis (SPTA). The interaction of LKA system control model with driver, steering system, data acquisition system and other external environment is established. Based on the model, 7 kinds of Unsafe Control Actions (UCA) are identified, and the vehicle-level safety constrains are proposed. 20 triggering conditions are identified from the perspectives of functional insufficiency and misuse. Taking the severity and controllability as the evaluation indexes, the risk assessment of each trigger condition is carried out, and the improvement measures are put forward. This study comprehensively reveals the way to realize the intended functional safety of LKA, and lays a foundation for the formulation of the control strategy of autonomous vehicles.