Reliability Assignment Method for Flight Control Computer Based on Fault Tree and Cost Function

Aiming at the reliability allocation problem in the design of redundancy flight control computer system of a certain type of teletype aircraft, a reliability allocation method combining fault tree and cost function is proposed. Firstly, the logical relationship between system functional failure and underlying equipment failure is analyzed by using the fault tree, and the functional relationship between the top event and the probability of occurrence of the bottom events is established; then, the concept of cost function is introduced, and the quantitative relationship between the generalized cost and the reliability of underlying equipment is established by combining the complexity of the equipment, the technical difficulty, the working time, and the working environment; next, the probability of occurrence of the top event and the generalized cost are considered to construct the optimization strategy for the reliability allocation scheme in optimization space; finally, according to the optimization strategy, the allocation scheme is solved iteratively in the optimization space. The results show that the allocation method can minimize the corresponding cost introduced by the system reliability enhancement by fully considering various factors on the basis of meeting the system reliability requirements.