ISO 26262 - The Relevance and Importance of Qualitative and Quantitative Methods for Safety and Reliability Issues Regarding the Automotive Industry

摘要

Safety and reliability are key issues of today's and future automotive developments, where the involved companies have to deal with increasing functionality and complexity of software-based car functions. New functionalities cannot only be found in the area of driver assistance - most of the new car functions are and will be safety related as for example in vehicle dynamics control or active and passive safety systems. The development and integration of those functions will strengthen the need of safe processes during the system development. The new upcoming automotive standard on functional safety (ISO 26262), which is derived from the generic functional safety standard IEC 61508 to comply with the specific needs to the application sector of E/E-systems in road vehicles, will provide guidance to avoid the increasing risks from systematic faults and random hardware faults by providing feasible processes and requirements. It is evident that aspects and methods of the safety and reliability engineering are implemented and suited methods are performed in the development process at an early stage. This is one of the requirements of the new ISO 26262, which introduces a so called automotive safety lifecycle to handle all those activities that are necessary to guarantee the functional safety of automotive E/E-systems. In the following, a brief overview of the upcoming automotive standard, its new safety life cycle and the connected activities in order to ensure functional safety for safety related systems will be given. The main aim of this paper is to show the relevance and importance of one of the major tasks within the ISO 26262: the process of the hazard analysis and risk assessment as it is currently performed in the automotive industry. With the help of an example from the automotive sector, the basic steps of this method to determine the automotive safety integrity level (ASIL) are explained. Depending on the ASIL, safety requirements need to be derived as a result of the new standard regarding safety integrity attributes. Furthermore, the connection of the automotive functional safety process with methods for qualification and quantification of safety and reliability issues will be explained in this paper. The Fault Tree Analysis will be used to exemplify one of these methods which are applied subsequent to the hazard analysis and risk assessment and which make a contribution to the validation and verification of the safety process.