StateEstimation for DelayManagement in Distributed RealTime CoSimulation via the Internet Typical distributed embedded realtime systems are composed of several subsystems developed by different, geographically distributed manufacturers. During the development process, these subsystems have to be integrated via realtime communication networks and tested. The verification can be simplified combining cosimulation and Software and HardwareInTheLoop (SILHIL) testing in a distributed cosimulation framework. In such a framework, software (SIL) and hardware (HIL) components can be tested against the model of a simulated plant. This way it is possible to detect design faults and integration problems while the subsystems are still located at their manufacturersxe2x80x99 sites.Realtime systems impose strict temporal and reliability requirements on the communication network connecting the subsystems. However, these requirements cannot be achieved using the Internet for communication in the distributed cosimulation framework. In this paper we introduce stateestimation as a delaymanagement technique to provide required subsystem inputs in time. Based on previous outputs and a simulation model of the remaining system, the mechanism estimates a subsystemxe2x80x99s future inputs. Using scheduling information about the realtime communication in the system, the framework can determine if an input packet is received in time. If not, the estimated packet is forwarded. As soon as the real input packet is received later, its content is compared with the estimated input and the operator is notified if the error between estimated and real input exceeds a configurable threshold.

Clock Synchronization in Context of the Distributed CoSimulation Protocol Today cosimulation methodologies are widely used for automotive system development. This approach supports distributed development and test of subsystems, which are engineered by different suppliers. The Functional MockUp Interface (FMI) as an open standard enables seamless integration of simulation models, tools and solvers. The recently published Distributed CoSimulation Protocol (DCP) is an open standard application layer communication protocol. It represents a solution for the integration of models or realtime systems into simulation environments. While the DCP was designed for low overhead and realtime capable operation, it does not specify the exchange of time information during simulation. The DCP currently relies on external mechanisms for time synchronization. In this paper, we propose an extension to the DCP, enabling time synchronization between DCP slaves and the master. This enables time triggered exchange of simulation data, applicable to the DCPu0027s realtime and nonrealtime operating modes. Therefore it becomes possible to synchronize time between participants of a distributed cosimulation scenario. Many applications may benefit from our approach, including hardware or softwareintheloop scenarios, or mixed realvirtual prototypes for e.g. automated driving. We demonstrate the functionality of our extension with a use case from the automotive domain, which implements a lane keeping assist system.