Priority-driven Swapping-based Scheduling of Aperiodic Real-Time Messages over EtherCAT Networks

Real-Time Ethernet (RTE) technologies are becoming increasingly popular, as they provide high bandwidth and are able to meet the requirements of industrial real-time communications. Among RTE protocols, the EtherCAT standard is suitable for motion control and closed-loop control applications, which require very short cycle times. As EtherCAT was specifically devised for periodic traffic, aperiodic real-time transmissions are far from being efficient, as they entail long cycle times. To overcome this limitation, this paper presents a general framework for priority-driven swapping-based scheduling of aperiodic realtime messages over EtherCAT networks, which uniformly covers both dynamic and static priority and allows for very short cycle times. The paper provides a description of the prioritydriven swapping framework, a schedulability analysis for both static priority and dynamic priority scheduling, and simulative assessments, obtained through OMNeT++ simulations.