Research on multi-leveled troubleshooting model based on Petri nets

Troubleshooting process or virtual maintenance is a complex system, and the research on it for troubleshooting process is still in the initial stage at present. The paper analyzes the discrete features of virtual troubleshooting process, and it presents a hierarchical model of troubleshooting process based on Petri net. The model consists of four layers. They are maintenance events layer, maintenance activity layer, basic maintenance activity layer and basic maintenance action layer. The procedure of modeling is in a sequential execution mode: analyze the features of troubleshooting, analyze the basic maintenance action of specific maintenance event, establish the top model and establish the subnet model. In this model, the packaged function of basic maintenance action can be repeatedly called by the Petri net. The model has been validated by the instance of virtual troubleshooting process of aircraft refuel-valve in the virtual maintenance platform.