Modeling and Supervisory Reconfiguration of a Dissimilar Redundant Flight Control System under Common-Mode Failures

Common mode failures may simultaneously impair multiple redundant channels, threatening redundancy independence and flight safety. Existing studies have mainly focused on safety architecture analysis, analytical redundancy design, and reliability allocation, while systematic research on failure propagation in closed loop flight control systems remains limited. In particular, insufficient attention has been given to channel degradation divergence and unified modeling for online reconfiguration. To address these issues, a unified framework for common mode failure propagation is established. On this basis, a dissimilar redundant control architecture is constructed by combining a state feedback channel and a proportional integral derivative channel. A supervisory reconfiguration strategy is developed by integrating multi source degradation assessment, credibility based control allocation, and hysteresis based hybrid mode switching. Simulation results from a longitudinal closed loop model show that the proposed strategy captures the divergent degradation of heterogeneous channels and triggers coordinated reconfiguration during fault propagation. As degradation increases, the control system transitions from baseline operation to weighted fusion and then to a safety preserving degraded mode, with control authority shifted toward the more credible channel. Compared with the case without reconfiguration, the proposed method yields smoother control responses and improved tracking performance.