Design Of Triplex Redundant Flight Control Computer Based On Flex Ray Bus

As core of the Unmanned Aerial Vehicle(UAV), demand on the flight control computer’s safety and reliability ranks first among all airborne subsystems. In order to enhance its safety and reliability, redundancy techniques are used in the design of the flight control computer. By improving fault diagnosis and fault-tolerant performance of the computer, influence of faults to the normally operating of the computer has been reduced to the least. Considering the actual demand of redundant control system from the example flight control computer, this paper devotes to the design of a flight control computer with triplex redundancy controller based on the FlexRay bus.Firstly, after analyzing the levels, structures and ways of working of redundancy as well as the data transmission mechanism of redundant channels, the goal of the research was set to the design of a hot backup and triple-similar-redundancy flight control computer based on the FlexRay bus. Upon these analyses, the whole design schemes of the system was finished.Secondly, in order to meet the design requirements of flight control system’s interface design, hardware was configured to the flight control computer. With modularization thinking, schematic diagram of kernel board minimum system, communication function units, bus communication link and the power module were designed. Meanwhile, corresponding printed circuit board(PCB) was developed, as well as the low level driver of different functional modules. For the realization of “software voting and hardware arbitration” voting function of the triplex redundancy flight control computer, theoretical design of arbitration board voting circuit was finished.What’s more, taking advantages of the function module partition of the UAV system software, a software for the flight control and management has been designed and developed. The software realized the goal of controlling and management scheduling of each module. Emphasizing the key points cross-modal synchronization, communication link data transmission, fault detection and diagnosis as well as system reconstruction and recovery of the triplex redundancy flight control computer in the design, fault detection and processing of system input and output have been implemented.Finally, hardware test platform of the flight control computer was constructed to verify the feasibility and validity of the single-channel hardware and low level driver. Meanwhile, by the way of injecting simulated faults, verification of redundancy management functions of the UAV flight control and managing software was carried out with the newly developed codes. Above testing results demonstrated that the designed triplex redundancy flight control computer can effectively processing most of the faults, greatly increasing the safely and reliability of the flight control system, and have met the designing requirements.