Hybrid modelling in discrete-event control system design

Simulation-based testing of discrete-event control systems can be advantageous. There is, however, a considerable difference between languages for real-time control and simulation languages. The Chi language, presented in this paper, is suited to specification and simulation of real-time control systems. The hybrid nature of the language makes it also suited to modelling of controlled machines. By connecting such models to models of control systems, simulation-based testing is possible. The language integrates a small number of orthogonal continuous-time and discrete-event concepts. The continuous-time part of Chi is based on DAEs; the discrete-event part is based on a CSP-like concurrent programming language. A case study is presented of a conveyor control system. The example illustrates the suitability of the language for discrete-event control system specification as well as for simulation-based testing of control systems