Latency analysis for the cooperation of event and time-triggered networks

The paper describes the analysis of cross network latencies occurring when federating an asynchronous, event-triggered CAN-bus and a synchronous time-triggered TTP/C network. The connection of networks is motivated by both cost-efficiency trade-offs in various network types and reasons of isolating highly critical from less critical communication. The intrinsic latencies incurred when crossing network boundaries are evaluated under various conditions - either in some form of synchronisation with a global time or in completely unsynchronised networks. The results from the formal analysis are compared to experimental results obtained in a mobile robot where the critical reactive control components are connected by a TTP/C network while additional sensor information improving the quality of control is obtained via a CAN-bus.