Unobservable fuzzy Petri net diagnosis technique
Ruoming An, Wei Liang · Aircraft Engineering and Aerospace Technology · 2013
Purpose The purpose of this paper is to resolve the problem of complex system diagnosis with unobservable events such as Hall thruster. Design/methodology/approach Fault class is defined by unobservable transitions subset. Every fault class is departed into four levels of alarm. The level of alarm for a fault class is identified by constructing basis reachability graph and computing j vector and basis marking. Certain factor values of diagnosis results are given by introducing two fuzzy operators. A two‐directional reasoning strategy is adopted which are forward reasoning and backward reasoning. Findings Using basis reachability graph and notions of basis marking and j vector, fuzzy Petri net with unobservable transitions can resolve the diagnosis problems with high accuracy and efficiency. Research limitations/implications The relationship between unobservable events must be known. Practical implications The method shows its superiority when it is applied to unobservable systems such as spacecraft. Originality/value A novel fuzzy Petri net framework for unobservable system multi‐fault diagnosis is put forward which introduces some new ideas.