Contributions to the design of real time distributed control systems

Embedded systems are computer-based systems that often must have deterministic temporal behaviour. The application software must ensure overall system performance in terms of hard real-time constraints, reliability and safety requirements. Often application constraints include distribution of input/output devices over the plant. In some other cases, distribution is needed to achieve demanding performance or dependability requirements. This paper presents a set of software tools that are integrated in the so-called Real Time Framework (RTF). The framework covers all the phases involved in the design of a real-time distributed control system from specification to code generation. The core of RTF is the definition of view-models of the system (Requirement, Architecture, Temporal and Process Models). RTF handles all 4 models offering different software tools that allow the user to define and analyse the system, before generating the application code. In particular, this paper deals with the tools developed that use the Architecture and Process Model in order to obtain application code for a distributed control system using CAN bus and the real-time operating system VxWorks. A case study that includes two control loops and a supervisor is presented to show the potential of the framework.