Integrating continuous-time and discrete-event concepts in modelling and simulation of manufacturing machines

Using simulation models for the development and testing of control systems can have significant advantages over using real machines. This paper demonstrates the suitability of the ¿ language for modelling, simulation and control of manufacturing machines. The language integrates a small number of powerful orthogonal continuous-time and discrete-event concepts. The continuous-time part of ¿ is based on DAEs; the discrete-event part is based on a CSP-like concurrent programming language. Models are specified in a symbolic mathematical notation. A case study is presented of a transport system consisting of conveyor belts.

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

Integrating Continuous-Time and Discrete-Event Concepts in Process Modelling, Simulation and Control

Currently, modelling of systems in the process industry requires the use of different specification languages for the specification of the discrete-event and continuous-time subsystems. In this way, models are restricted to individual subsystems of either a continuous-time or discrete-event nature. It is our aim to integrate such models, by using one language for the specification of complete plants or production units. For this purpose, we introduce the language Chi in this paper. This 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. Models are specified in a symbolic mathematical notation. A case study is presented of a plant for the biochemical production of ethanol. The production takes place in a number of fermentors in a fed-batch fashion. The fermentation process and the control system, which controls the various valves and pumps and schedules the different batches, are both specified in Chi.. The example illustrates the relevance of integrating continuous-time and discrete-event concepts