Impact Analysis of Electrical Fast Transients on FlexRay In-Vehicle Networks

Distributed vehicular control systems are responsible for safety-critical applications, depending on communication protocols. In this context, the FlexRay protocol is frequently applied for electronic control unit interconnection in critical applications. Thus, it must be tested in different fault scenarios to verify if the protocol could comply with hard timing constraints. Typical faults that have been studied are electrical fast transients, in which power switching systems can generate transients that degrade in-vehicle communication. Recent efforts focus on the specification of test methods for electromagnetic compatibility in communication transceivers, but without considering the negative impact on critical control system messages and its periodicity. This work presents a contribution by exploring the IEC 62228-3:2019 standard to guide the application of a test method with a specific test board to evaluate the impact of these faults on the control law performance of critical automotive control systems based on FlexRay protocol. The results show that during the test scenarios using the fault injection method, the transients cause performance degradation peaks between 2.9 and 94.5 μs, much higher compared to a typical FlexRay delay. The results emphasize that critical control systems must be stressed with consistent tests to map fault behaviors, observing the operation limit under faults.