A DEVS-based approach for modeling and simulation of hybrid variable structure systems

The modular-hierarchical modeling subdivides a system into dynamic describing atomic, and structure describing coupled systems. Due to the usally static structure of coupled systems, it can sometimes be hard to realize a component-oriented mapping of real system elements in model components. Hence, several approaches to model structural changes are developed, which are roughly classified in the paper. Starting with the classical DEVS-theory and a specific extension for hybrid systems, this paper presents a modular-hierarchical modeling approach, that supports the specification of time-varying structures on the coupled system level. The possible structural variability comprises changes of the component structure and the coupling relations. The basic modeling principle is demonstrated using the example of an automated manufacturing cell. Because variable structure modeling of hybrid systems brings advanced requirements to the simulation methods, the general structure of a possible simulation approach is presented.