Research On Fault Detection And Redundancy Management For Flight Control Computer

With the advantage of no casualties,broad application and high cost-efficiency,Unmanned Aerial Vehicle(UAV)has been developed rapidly for the applications unfriendly to manned aircraft.Since UAV is deployed in special and complex environment,the requirement for its reliability is high.To satisfy the requirement,redundancy technology has been utilized in all aspects of UAV designs.High performance Flight Control Computer(FCC),as the core of UAV flight control system,applies redundancy technology in the design of hardware structure.Thus it is important and valuable to study the Fault Detection Algorithm(FDA)and Redundancy Management Strategy(RMS)in software scale,based on the specialty of FCC hardware redundancy allocation.The paper first studied the structure and redundancy resource allocation of one certain type of redundancy flight control system.It covered the sensor subsystem,actuator(rudder loop)subsystem and FCC.Above all,the quantitative analysis of the reliability,hardware resources and software operation environment was conducted,which provided the foundation of FDA and RMS.Furthermore,in FDA aspect,the dissertation used failure modes and effects analysis to analyze the fault mode of Control Unit(CU),Interface Unit(IU)and FlexRay bus.For different types of faults,heartbeat detection with two detection phase,self-detection based on task status,state feedback,expert system,and request response algorithms have been proposed.Besides,in RMS aspect,the "Coordination" working pattern has been determined by analyzing "Comparison" and "Coordination" mode.According to the data flow on FlexRay bus,the transmitting and receiving time slots of CU,IU are assigned.The reconfiguration and recovery design of CU and IU are completed,including "priority rotation" reconfiguration strategy,key data screening and process design of forward recovery and backward recovery methods.In all,the redundancy flight control software was developed under ?C/OS-? real-time operating system,which combines FDA and RMS.To verify its function and performance,a fault injection software was developed,a simulation environment was established,and tests were conducted on flight control and redundancy management function and performance.The results showed that the redundancy flight control software can achieve the functions of flight control and redundancy management,with real-time fault detection and the ability of reconfiguration and recovery,satisfy the design requirement.