Safety-Driven Development and ISO 26262

Taxonomy to Unify Fault Tolerance Regimes for Automotive Systems: Defining Fail-Operational, Fail-Degraded, and Fail-Safe

“…This first main category can be divided into two subcategories. In the first subcategory [24,40,46,47], a core functionality of the fail-operational system is maintained to achieve a defined state. The sole publication of the second subcategory [27] requires the system to maintain full functionality until the defined state is reached.…”

“…The fail-safe property of a system is commonly described as the transition into a defined state (usually referred to as "safe state") in the event of failures [24,26,29,34,35,[40][41][42]47]. While most definitions describe the safe state as a specific condition of the analyzed (sub-)system [24,26,29,34,35,41,47], Thorn et al [40, p. 90] argue that the safe state is a "condition where the vehicle and occupants are safe." This corresponds to Wood et al [42, p. 135] who describe a failsafe system to continue operating "in a safe state in the event of a failure."…”

Design of a Testing Tool Based on Fault Injection for Functional Safety

“…To standardize the safety behaviors involved in product design, research and development, testing, and post-processing of automotive electronics and electrical systems, the International Organization for Standardization released ISO 26262 "Road vehicles --Functional safety" in 2011 [1], aiming to reduce the uncontrollable risks caused by failures in automotive E/E systems. The standard covers the life cycle of automotive systems and provides a basis for product development testing based on the V-model, encompassing the concept phase and system design (software and hardware levels) [2]. Fault injection testing (FIT) [3,4], as a recommended testing method in various stages, injects potential faults into the system under test to detect whether there are failure risks under fault conditions, thereby verifying the effectiveness of the system's safety mechanisms.…”