Formal system interactive failure analysis method based on systems theoretic process analysis model

Interactive failures are failures caused by two or more components that often occur in complex systems when the system is modified, upgraded, or simply designed inadequately. However, the official guideline provided, namely, common cause analysis, cannot discover these problems. It cannot establish a complex interactive system model, nor can it provide a unified analysis method for all parts of the system. Another method, systems theoretic process analysis, is limited to the control system. To solve this problem, a method called system theoretic formal analysis method (STFAM) is proposed in this paper. STFAM establishes a system-component-interactive model that provides an abundance of interactive information for failure analysis and presents a unified model to support the analysis of multiple components in the system. It is divided into three steps. First, a hierarchical system structure is built and then transformed into a formalized state machine. Next, the interactive failures are determined and converted into a linear temporal logic or computation tree logic model. Finally, NuSMV is used to verify the model and record the results. To evaluate the proposed method, a practical problem that occurred in full-authority digital engine control, in which in some cases, the valve closes for unknown reasons until the system is reset is presented. An analysis of the issue demonstrates the effectiveness of our method.