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Redundant techniques are widely adopted in vehicle management computer(VMC) to ensure that VMC has high reliability and safety.At the same time,it makes VMC have special characteristics,e.g.,failure correlation,event simultaneity,and failure self-recovery.Accordingly,the reliability and safety analysis to redundant VMC system(RVMCS) becomes more diffcult.Aimed at the diffculties in RVMCS reliability modeling,this paper adopts generalized stochastic Petri nets to establish the reliability and safety models of RVMCS.Then this paper analyzes RVMCS operating states and potential threats to flight control system.It is verifed by simulation that the reliability of VMC is not the product of hardware reliability and software reliability,and the interactions between hardware and software faults can reduce the real reliability of VMC obviously.Furthermore,the failure undetected states and false alarming states inevitably exist in RVMCS due to the influences of limited fault monitoring coverage and false alarming probability of fault monitoring devices(FMD).RVMCS operating in some failure undetected states will produce fatal threats to the safety of flight control system.RVMCS operating in some false alarming states will reduce utility of RVMCS obviously.The results abstracted in this paper can guide reliable VMC and effcient FMD designs.The methods adopted in this paper can also be used to analyze other intelligent systems’ reliability.
Redundant techniques are widely adopted in vehicle management computer (VMC) to ensure that VMC has high reliability and safety. At the same time, it makes VMC have special characteristics, eg, failure correlation, event simultaneity, and failure self-recovery. Accredited, the reliability and safety analysis to redundant VMC system (RVMCS) becomes more diffcult. Aimed at the diffculties in RVMCS reliability modeling, this paper adopts generalized stochastic Petri nets to establish the reliability and safety models of RVMCS.Then this paper analyzes RVMCS operating states and potential threats to flight control system. It is verifed by simulation that the reliability of VMC is not the product of hardware reliability and software reliability, and the interactions between hardware and software faults can reduce the real reliability of VMC substantially. Morerther, the failure undetected states and false alarming states inevitably exist in RVMCS due to the influences of limited fault monitoring coverage a nd false alarming probability of fault monitoring devices (FMD). RVMCS operating in some failure undetected states will produce fatal threats to the safety of flight control system. RVMCS operating in some false alarming states will reduce utility of RVMCS. these results abstracted in this paper can guide reliable VMC and effcient FMD designs.The methods adopted in this paper can also be used to analyze other intelligent systems’ reliability.