Daniel Rossier, Reconfigurable Embedded Digital Systems, HEIG-VD/HES-SO, Switzerland
Patrick Gerber, Reconfigurable Embedded Digital Systems, HEIG-VD/HES-SO, Switzerland

Usually, critical applications such as motion control or telemetry applications run on top of a realtime operating system which provides an adequate execution environment with respect to realtime (temporal) constraints. On the other hand, user interfaces and other facilities (communication service, database management, etc.) run on a separate PC which is connected to the remote platform by means of field busses (Ethercat, CAN, etc.). For a couple of years, there are several solutions which give the possibility to run hard-realtime and non-realtime applications on the same machine using virtualization technics at different levels. It is the case for example of VxWins from WindRiver or RTX (Realtime extension for Windows). In the open source community, RTAI and Xenomai are both examples of such hard realtime extensions.

Such realtime extensions gain a fascinating interest in the embedded world since the power of last generation microcontrollers and DSPs enable the deployment of many complex software applications while keeping the performance at a high level. The advantage of this approach is to have a convenient development environment for embedded applications using traditional software libraries for GUI, mathematics, communication services, etc. without the need to rewrite some code on a specific RTOS. The critical applications are running in a (hard-)realtime domain which is normally well isolated from the non-realtime domain in which the non-critical applications run.

In this paper, we present a novel embedded system devoted to critical motion control applications and the software architecture based on Linux/Xenomai that we are using for managing both critical and non-critical applications. First performance results as well as ongoing research work torwards an improved virtualized environment for critical realtime applications are presented.