Research on dissimilar redundant flight control computers of large civil aircraft

Basic research is carried out on the redundant flight control computer (FCC) of China's self-deve-loped civil aircrafts. A novel redundant FCC is designed, which is appropriate for the fly-by-wire (FBW) system of China's large civil aircrafts. Also two principles on FBW architectures design are proposed: satisfying the system reliability requirements and satisfying the FO/FO/FO fault-tolerant grade. Then seven suggestions on the FCC design are made based on these two principles. Accordingly, the redundancy number and fault-tolerant architecture of the FCC are confirmed. Specifically, four-redundant dissimilar fault-tolerant FCC are adopted, and each redundant channel is constituted of two lanes: a control lane and a monitor lane, and each lane contains two different program versions in order to balance the reliabilities of software and hardware. The proposed FCC's reliability is evaluated through Petri nets (PN) models with comparision with the redundant FCC of B777 and A320. The results show that the designs can satisfy the civil aircrafts' reliability requirements. And in the other hand, the architecture of the design is reasonably simple and can save hardware resources. In a word, the designs can be applied to the FBW's development for the domestic civil aircrafts.