Reliability Analysis of Full Authority Digital Electronic Control System Based on Multi-state Binary Decision Diagram

To efficiently assess the probabilistic safety of full authority digital electronic control system within aeroengine, a system reliability model was established, using the loss of thrust control as the boundary condition. A probabilistic safety assessment method based on a multi-state binary decision diagram was proposed and subsequently verified through case simulation. For the multi-state of full authority digital electronic control system, an analysis was conducted to identify the system units that contribute to the occurrence of multi-state events, leading to the establishment of a reliability model for the system. A multi-state fault tree was generated, with the loss of thrust control designated as the top event, and this fault tree was analyzed in depth. The method involved prioritizing traversal and constructing a multi-state binary decision diagram model for probabilistic safety assessment, allowing for the calculation of the probability expression for each state of the system. Engineering cases were presented, and MATLAB simulation analysis was employed to obtain the probability curves of each state of the system at various times (t), thereby validating the effectiveness of the proposed method. The results indicate that this evaluation method can rapidly compute the probabilities of system states across all levels using mathematical expressions, addressing the challenges of low computational efficiency and the limitations of traditional reliability analysis methods, which are typically confined to small models. This approach can be applied to aerospace engine electronics with n sensors in the control system.