Verifikationsmethode für Dienstorchestrierungen modularer verfahrenstechnischer Anlagen mittels Petri-Netzen unter vorherrschenden Dienst- und Prozesswertabhängigkeiten

Abstract

The current development of the highly volatile markets for goods in the process industry requires versatile production systems. One approach to this is modular plants. These modular plants provide their process engineering functions encapsulated as so-called services. Services are brought into a superior process orchestration layer in so-called orchestrations in step-transition sequences in order to run the desired production processes in the modular systems. The Module Type Package in AutomationML format has established itself as an essential information carrier for modules. It enables almost automatic integration of modules into the process orchestration layer. The engineering of modular plants is very complex. Modules can have dependencies at both service and process value level. These dependencies can have an influence on the feasibility of orchestrations. For this purpose, dependency types are defined in this thesis. These can occur both internal and across modules and at service and process value level. In addition, dependencies are examined on the basis of physical interactions at module boundaries. In order to ensure industrial application of the dependency types, modelling in AutomationML is carried out in accordance with the modelling of the Module Type Package. In addition, the dependencies are modelled in a defined Petri net. This allows the services and all dependencies of a modular plant to be modelled in one combined Petri net. This plant Petri net forms the basis for the verification of the feasibility of orchestrations within the plant. For this purpose, known analyses for Petri nets are carried out. A transformation of the orchestrations into firing sequences is introduced and orchestrations are checked on the basis of the reachability graph of the plant Petri net. Due to the limited software tools, very large plant Petri nets must be reduced both domain-specifically and structurally. For this purpose, reduction rules are introduced and applied. This thesis can form a basis for the verification of the feasibility of orchestrations in modular plants. However, there are limitations in the area of modelling and analysis, which are discussed in detail in the thesis.