An efficient method for synchronizing clocks of networked ECUs in automotive systems

Advanced active-safety-critical automotive applications require close coordination of different activities including sensing, processing and actuations, typically performed by different Electronic Control Units (ECU) connected over a communication network. It is imperative that ECUs executing these tasks have a common reference of time. In a distributed system, a periodic resynchronization is a common approach to ensure this. In this paper, we have proposed a new protocol for clock synchronization keeping resource-constraints automotive systems. Our specific contributions include: (a) as compared to standard treatment of drift as a linear function of time, we use a realistic non-linear model of drift, and (b) in order to minimize communication overhead, we propose an algorithm to anticipate the time at which a specific ECU would go out of sync and participate only such identified ECUs for resynchronization instead of all ECUs, as traditionally done. Analytical results show that the proposed protocol incurs minimal communication as well computational load on the ECUs.