Design considerations for the diagnostics concept of a fail-operational steering system for an L4/L5 automated vehicle

Joint presentation by Chassis Autonomy and Roben Automotive. While the origins of diagnostics systems in vehicles are the powertrain systems, they have since expanded to other domains of the vehicles. The diagnostics have also become more and more disconnected from their original focus of emissions control systems; going as far as OBD now being a generic term. In this presentation, we focus on a steering system that is to be used in vehicles without a steering wheel. The diagnostic concept should not �just� ensure that failure modes are found but should also prove there is sufficient diagnostic coverage to meet ASIL-D demands. Since Functional Safety, however, assumes there is still a driver in the vehicle further steps are needed. The diagnostic concept must ensure that after a failure has been recognized that the steering system remains operational (i.e. fail-operational).