Method of Testability Index Determination Based on Generalized Stochastic Petri Net

As an important performance of equipment system, testability is always omitted in the traditional availability analysis. Testability design is an effective way to realize the fault detection and isolation. Determining testability index is the chief step of testability design. It needs to consider the influence factors of testability such as the requirement of system availability, reliability, maintainability, supportability and so on. A testability requirement analysis model is built based on generalized stochastic Petri nets (GSPN), which is used to determinate testability index. The reachable states are analyzed based on the model and the Markov chain is constructed. The state transition matrix is created and the system steady state probability is gained. The relationship between the steady state availability and testability parameters was revealed and the testability parameters are reasoned. The validation results of an example show that the method is an effective method to determine testability index such as fault detection rate and fault isolation rate.