Jörg Preußig

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This contribution reports on a case study in the application of tool-based methods for a systematic analysis of hybrid systems. In particular, the study is focussed on continuous processes controlled by logic controllers, as this class of hybrid systems is widespread among process industry plants. To achieve comparable results, all methods and tools under(More)
We describe two approaches to derive Timed and Linear Hybrid Automata from continuous models given as systems of ordinary diierential equations. A semiquantitative modeling method is applied which yields a qualitative description of the system dynamics and quantitative bounds for the residence times in the discrete states or the state variable derivatives.(More)
ion must be amenable to automated analysis. Typically, this is achieved by ensuring that the abstraction belongs to a restricted class of automata. In previous work, we proposed that the abstractions H 0 be linear hybrid automata [1], in which the continuous dynamics are given as constant polyhedral di erential inclusions. For these automata, reachable(More)
In this paper we integrate two diierent approaches for the speciication and veriication of timed systems being used in control theory and computer science. These are the timed condition/event systems and the timed automata formalisms. Our main result states that timed condition/event systems can be eeciently transformed into timed automata which then can be(More)
The paper presents a concept for the reachability analysis of switched continuous systems in which switching only occurs when the continuous state trajectory crosses thresholds defined by a rectangular partitioning of the state space. It combines an existing approach for approximating such systems by rectangular automata with an existing reachability(More)
An approach to the formal verification of logic controllers for processes with switched continuous dynamics is presented. The method builds on modular, timed discrete event models of the plant and the controller. Subsystems with continuous dynamics are approximated algorithmically. The formal verification consists of determining the reachable discrete(More)
The paper describes a model-based approach to the formal verification of sequential control programs for chemical processes. It is assumed that the control software is represented as a Sequential Function Chart (SFC) which may include timing constraints for the control actions. The verification method is based on a timed Condition/Event (C/E) model of the(More)
This paper describes the use of timed Condition/Event (C/E) systems, a real-time extension of the C/E system framework introduced by Sreenivas and Krogh, for building models of chemical plants in a modular fashion and as a basis for the model-based analysis of their discrete control. The approach is illustrated by applying it to the safety control logic of(More)