Evaluation of the reliability of non-coherent systems using Binary Decision Diagrams

While many systems are coherent, some systems have non-coherent structure due to their negative feedback loops and redundant loops. A system is non-coherent for a component if it is in a failed state when the component is in a working state, and when the component fails, the system is restored to the non-failed state. In this paper, we propose a straightforward method to evaluate the imprecise reliability of non-coherent systems using binary decision diagrams (BDD) and imprecise probabilities. The system components are categorized into three types according to their coherency inside the studied system: positively coherent, negatively coherent and non-coherent. The reliability of components is represented by intervals. The imprecise system reliability is obtained using operations performed on the different paths of the BDD. A numerical example is also given in order to illustrate the proposed method. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.