Formal design of hybrid systems

Abstract

A hybrid system is a system containing both of time-evolving components and event-driven components. A formal approach is explored in this paper, based on Extended Duration Calculus (EDC), for the development of hybrid systems. A typical example of hybrid system from modern control theory, a two-level adaptive control system, is used for illustrating our approach. Its high level consists of an event-driven supervisor which reacts to the change of plant structure, and its time-evolving low level consists of adaptive controllers and other components. Firstly performance specifications and system specification of the case are formulated in EDC; then they are refined stepwise into specifications of the supervisor and the low level components. Our approach emphasizes the interface between the two kinds of components in the hybrid system.