Marte Framework: a Middleware for Real-time Applications Development

The Multi-threaded Application Real-Time executor (MARTe) is a C++ framework that provides a development environment for the design and deployment of real-time applications, e.g. control systems. The kernel of MARTe comprises a set of data-driven independent blocks, connected using a shared bus. This modular design enforces a clear boundary between algorithms, hardware interaction and system configuration. The architecture, being multi-platform, facilitates the test and commissioning of new systems, enabling the execution of plant models in offline environments and with the hardware-in-the-loop, whilst also providing a set of nonintrusive introspection and logging facilities. Furthermore, applications can be developed in non real-time environments and deployed in a real-time operating system, using exactly the same code and configuration data. The framework is already being used in several fusion experiments, with control cycles ranging from 50 microseconds to 10 milliseconds exhibiting jitters of less than 2%, using VxWorks R ©, RTAI or Linux. Codes can also be developed and executed in Microsoft Windows R © and Solaris R ©. This paper discusses the main design concepts of MARTe, in particular the architectural choices which enabled the combination of real-time accuracy, performance and robustness with complex and modular data driven applications. ∗ See the Appendix of F. Romanelli et al., Proceedings of the 23rd IAEA Fusion Energy Conference 2010, Daejeon, Korea INTRODUCTION MARTe [1] is a framework tailored at the design and development of real-time control systems. The kernel of MARTe uses a C++ multi-platform library named BaseLib2 [2]. The main ideas behind the original design of the framework were the modularity and portability of its applications. In particular, a strong effort was made in order to allow a robust simulation environment that allows both the models to be simulated with the hardware in the loop and the control algorithms to be validated offline. This is achieved by providing a clear development boundary between the algorithms, hardware and system configuration. Being multi-platform it also allows to debug and develop in non-real-time environments, where better developing tools are usually available. Currently the framework runs in Linux, Linux with RTAI [3], VxWorks R © for PowerPC R ©, Solaris R © and Microsoft R © Windowstm. The framework components are configured using a common language, designed to be as simple as possible, but complete enough to provide a clear way of describing the problem. The structure is similar to XML, where the syntax rules are validated by a BaseLib2 parser, whereas the actual validity of the arguments is performed by the component (i.e. no validation schema is available). An example of a configuration is shown in Listing 1. The configuration file is translated into a database of named objects that can be browsed using the object addresses in the database. By parsing the configuration file, the framework automatically creates and configures instances of all the declared objects. A messaging mechanism uses the database to provide a standard interface for communication between objects. This is the preferred , Culham Science Centre, OX14 3DB, Abingdon, UK Proceedings of ICALEPCS2011, Grenoble, France THDAULT06 Embedded + realtime software 1277 C op yr ig ht c ○ 20 11 by th e re sp ec tiv e au th or s— cc C re at iv e C om m on sA tt ri bu tio n 3. 0 (C C B Y 3. 0) +H t t p S e r v e r = { C l a s s = H t t p S e r v i c e P o r t = 8084 } +MARTe = { C l a s s = MARTeContainer +RTThread1 = { C l a s s = RealTimeThread +SurfaceTemperature WOPL 14 = { C l a s s = S u r f a c e T e m p e r a t u r e 1 D C a l c u l a t i o n S p e c i f i c H e a t = 1 . 925000 e+03 T h e r m a l C o n d u c t i v i t y = 1 . 900000 e+02 Del taT = 0 . 0 1 N s l i c e s = 40 Inpu tS igna l N a m e s = { 0 = {Q WOPL 14 } } Outpu tS igna lNam es = { 0 = { SurfaceTemperature WOPL 14 } } } +D i v e r t o r T h e r m a l C a l c u l a t i o n s = { . . . W a l l s P o w e r P a r t i t i o n C l a s s = { Type = W a l l s P o w e r P a r t i t i o n C l a s s P a r t i t i o n T a b l e = { 0 = { 0 = { 0 . 3 0 . 3 0 . 3 0 . 3 } 1 = { 0 . 7 0 . 7 0 . 7 0 . 7 } } . . } . . . } } . . . Listing 1: A small fraction of a configuration file from the real-system responsible for the JET plasma wall load protection system (WALLS).