The Development Framework: work in progress towards a real-time control system design environment

This paper describes work in progress on two extensions to the environment of a Development Framework for the design of control system software; hybrid system design and design of dependable systems. The Development Framework automatically converts a control engineering specification into a parallel implementation. Hybrid control systems are a combination of real-time control law and discrete-state logic. The Framework can be adapted so that it may handle discrete events such as mode switching. A statechart tool, Statemate [i-Logix95], is used to specify and model discrete-state components. The design phase of the Development Framework supports the integration of the two sets of specification. Initial work to support the design of dependable systems has included the implementation of an interface between the Framework design model and the dependability modelling tool, SURF-2. Stochastic Petri net models of selected fault-tolerant mechanisms are currently supported. The models enable sensitivity analysis and comparison of competing architectures.