A fault monitor for automated manufacturing systems using a hybrid Petri nets formalism

Fault monitoring is an essential requirement for safety and reliability of industrial systems. The paper presents a novel event-based online monitoring technique for automated manufacturing systems, ensuring timely and accurate detection of system failures. The monitor model is based on first-order hybrid Petri nets, ie, Petri nets that make use of first-order fluid approximation. The proposed fault analysis technique relies on a modular framework, so that elementary monitors can be connected with other monitors to check more complex systems while avoiding the state-space explosion problem. In addition, the presented monitor detects system faults as soon as possible, before the maximum execution time assigned to each task. Several examples and an application to an automated manufacturing system proposed in the related literature enlighten the simplicity and modularity of the technique.