Research On Redundancy Management For Triplex Redundant Flight Control Computer

Recent years have been seeing the unprecedented development of various unmanned aerial vehicles(UAVs)and their growing applications in both military and civilian domains.As the core of the flight control system,the reliability of the flight control computer has become more and more important,especially for high-altitude long-endurance UAVs,which require the flight control computer to work reliably for long periods of time.The application of redundancy technology makes it possible to significantly improve the reliability of flight control computer.Aiming at the problem of insufficient reliability and lacking fault tolerant ability of the existing flight control computer,the paper constructs a three-module redundancy architecture of central processing unit(CPU),and on the basis of which,the redundancy management strategy is designed.To solve the problem of accumulated clock deviation among CPUs in distributed flight control computer,the clock synchronization algorithm is designed in this paper,and realizes the time and information synchronization of CPUs through the exchange of time stamp information and the adjustment of local logic clock.In order to avoid the influence caused by the partial failure of CPUs,majority voting algorithm and votes voting algorithm are proposed for different signal characteristics,and the optimal results are selected and outputted,which improves the fault tolerant ability of the system.In addition,for the faults of CPUs and bus nodes,the schemes of reorganization and reconstruction are proposed.By removal,recovery and reconstruction of the fault sources,the redundant resources can be reused which give the system capability of self-healing and improve the reliability.Finally,the functions of synchronization,voting and reconstruction in redundancy management scheme are tested in different fault conditions simulated by external fault injection.The closed-loop simulations test the flight control and management functions of the triplex redundant flight control computer.The test results above show that the designed redundancy management scheme is reasonable and effective,and the system performance meets the design requirements.