A Component-Based Framework for Distributed Control Systems

The paper presents a two-level software framework for distributed embedded applications. At the top level, an application is conceived as a composition of embedded actors that communicate transparently by exchanging labeled messages (signals), independent of their allocation onto network nodes. Signals are exchanged at precisely specified time instants, in accordance with the concept of distributed timed multitasking (DTM). The combination of actors, signal-based communication and DTM provides a framework for the development of open yet predictable embedded systems. At the lower level of specification, actors are modeled as software objects that are configured from executable components - basic, composite and modal function blocks, as well as supervisory state machines. Actor behaviour is specified with a hybrid executable model - a clocked event-driven state machine operating in conjunction with modal function blocks, which can be used to implement a broad range of applications such as sequential, continuous and hybrid control systems