Input Event Modeling for Discrete-Event Controllers: A Petri Net Approach

The modeling of controllers for discrete-event systems commonly uses state-based formalisms, such as state diagrams and Petri nets. These modeling formalisms heavily rely on the concept of events. From an automation system perspective, events can be characterized as changes on a signal or other variable. Several types of events can be defined, considering different types of signals, including Boolean and multi-valued signals, as well as different types of dependencies in terms of the evolution of the signals. For the presented work, the model of the controller is produced using IOPT nets, a non-autonomous Petri nets class. In this paper, a set of translation rules for several types of events is proposed allowing the generation of behaviorally equivalent IOPT Petri net models, which will be executed concurrently with the main model constrained by the translated events. An example is presented to illustrate the benefits associated with the usage of the proposed translation rules. We conclude by identifying some future work, namely their integration with the IOPT-Tools framework, which is freely available to use.