On ISO 26262 Compliance and Safety Assurance for Autonomous Vehicles using STPA

Abstract

Recently, the use of electrical and electronic control systems has been increasing in various industries. In particular, in the automobile industry, unlike mechanical vehicles in the past, today's vehicles have a significant increase in complexity as the system of the electronic control device increases, and accordingly, the overall system malfunction increases. Although IEC 61505, a functional safety specification for electrical / electronic / programmable electronic safety management systems across industries, does not reflect the specificity of the automotive field. Therefore, ISO 26262, an international standard for automotive functional safety, was established and distributed based on IEC 61508. ISO 26262 presents safety analysis method throughout the life cycle from concept stage to operation and disposal. Typical safety analysis methods include PHA (Preliminary Hazard Analysis), HAZOP (Hazard and Operability), FMEA (Failure Mode and Effect Analysis), and FTA (Fault Tree Analysis). However, this analysis method has limitations in analyzing the interactions between modern complex systems. To overcome this, a STPA (System Theoretic Process Analysis) technique based on MIT's STAMP (System Theoretic Accidents Model) model has been proposed. In this paper, as a safety analysis method using STPA, a usecase that defines the system operation process and a risk identification method using STPA are presented. Applying this method to the system development process can contribute to deriving potential risks, causes of risks, and safety requirements, and is expected to improve the quality of the system and reduce costs. For the verification of this study, the ACC (Adaptive Cruise Control) case among the ADAS (Advanced Driver Assistance System) functions of the vehicle is applied and presented.