Research & Design On Fault-tolerant Flight Control Computer For Uav

Comparing with the common unmanned aerial vehicles (UAVs), high-altitude long-endurance UAVs need for higher flight safety because of their high cost and long-endurance mission. The use of high-reliability flight control computer is one necessary way to ensure the safe flight of UAV. The general way to improve the reliability of the flight task of flight control computer is using fault-tolerance technology. Aiming at flight safety of high-altitude long-endurance UAVs, the paper described the design on a CAN-based fault-tolerant flight control computer which used Triple Module Redundancy (TMR).According to the requirements of UAV flight control and management function, in accordance with the design principle of fault-tolerant flight control computer, overall program of system design was studied and designed. According to the structural features of the fault-tolerant flight control computer, three key issues which included the inner CAN communication of system, the task synchronization of the three central processing units and the redundancy management of system redundancy resources were proposed.In response to the three key issues, detailed design was carried out. Upper-level protocol of CAN communication which included CAN frame communicating and identifier distributing was proposed. Task synchronization which used the median-based consistency synchronization algorithm and achieved initial synchronization and re-synchronization after exceeding the maximum asynchronous offset was designed. Solution of system redundancy management was given. In the solution, fault detection and fault diagnosis strategy based on CAN and the voting mechanism was designed, system reconfigurable logic under fault and system recovery logic under the transient fault were designed.To verify correctness and rationality of the overall program of system design and the practical feasibility and performance of the solutions of the key issues, testing experiments and semi-physical simulation experiment were desighed. Special testing and simulation results showed that: the overall program of system design was reasonable, and the solutions of key issues were well-functioning and good performance, and the sample fault-tolerant flight control computer met the design requirements.