Comparing Different Levels of Technical Systems for a Modular Safety Approval—Why the State of the Art Does Not Dispense with System Tests Yet

Björn Klamann,Hermann Winner

doi:10.3390/en14227516

Abstract

While systems in the automotive industry have become increasingly complex, the related processes require comprehensive testing to be carried out at lower levels of a system. Nevertheless, the final safety validation is still required to be carried out at the system level by automotive standards like ISO 26262. Using its guidelines for the development of automated vehicles and applying them for field operation tests has been proven to be economically unfeasible. The concept of a modular safety approval provides the opportunity to reduce the testing effort after updates and for a broader set of vehicle variants. In this paper, we present insufficiencies that occur on lower levels of hierarchy compared to the system level. Using a completely new approach, we show that errors arise due to faulty decomposition processes wherein, e.g., functions, test scenarios, risks, or requirements of a system are decomposed to the module level. Thus, we identify three main categories of errors: insufficiently functional architectures, performing the wrong tests, and performing the right tests wrongly. We provide more detailed errors and present examples from the research project UNICARagil. Finally, these findings are taken to define rules for the development and testing of modules to dispense with system tests.

Highlights

The safety validation in the automotive industry still focuses on the vehicle or system level
With the new concept of a modular safety approval, we provide the opportunity to dispense with system tests
This process can be as erroneous as any other decomposition process that needs to be considered in the safety validation

Summary

Introduction

The safety validation in the automotive industry still focuses on the vehicle or system level. Their systems have become increasingly complex so that today’s processes require comprehensive tests to be carried out even at a low hierarchical level, e.g., on component level. Different sets of modules may be combined to various use cases without the need for a safety approval for every different combination [7]. To realize such a modular approach, it is crucial to differentiate between the development and testing of systems and of said modules

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Discussion

Conclusion