The onboard hydraulic oil source system has some fault-free behaviors with normal distributed periods and some faulty ones with exponentially distributed periods. The model of the onboard hydraulic oil source system was built by normal-stochastic PNs which combined firing periods with normal and exponential distribution. A method was proposed for the the firing periods parameters identification, which was the mean valuemand the periods standard deviationσfor normal distribution or the exponential distribution mean valueμ. The simulation results showed that the computing operating periods parameters were consistent with the real operating periods parameters.
