| With the rapid development of UAVs, "High-altitude long-endurance(Hale)" has gradually become one design goal of large high-end UAV. Hale results "poor working conditions, long uninterrupted run time" problem, which makes more stringent requirements to the reliability to UAV. As the core component of the UAV, flight control computer’s reliability is particularly important. In this paper, based on the mature ISA bus flight control computer(FCC), designed and developed the CAN bus FCC, which has "high reliability, high scalability, high maintainability".Internal communication bus is the main reasons to limit the ISA bus FCC to further improve the reliability.So choose CAN bus as the internal bus, which is more scalable, easier to implement redundancy. And designed backward compatibility, flexible connection overall communications program. Using the idea of "universalization", the logical and interface management module is integrated on a single board, forms a universal core board which is easy to maintain. According to the core card’s scarce layout space, weak CPU processing ability, proposed the "CAN-IP extension interface" as the controller hardware implementation. Designed and implemented the underlying API and upper level communication rules, which is comprehensive and easy to use. Ensured the FCC’s internal communication is simple and reliable. Designed distributed software architecture, and multi-unit management techniques, making single-channel CAN bus FCC to be suitable for engineering application. By increasing the number of core board, make the control unit to be redundant. In the software level, propose "collaborative method" as a fault tolerant strategy, and use the most simple and reliable methods to achieve fault diagnosis, system reconfiguration and fault recovery. The mission reliability of FCC has been greatly improved.In this paper, the CAN bus computer has been fully validated. Using sophisticated real-time simulation system verified the flight control computer basic functions, including control logic, each unit’s CPU load and CAN bus load; Using fault injection, fully tested the computer fault tolerance function. Test results show fault-tolerant flight control computer CAN bus achieves the design goal. |
