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Safety and reliability synthesis of systems with control loops
Author(s) -
Kumamoto Hiromitsu,
Henley Ernest J.
Publication year - 1979
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690250112
Subject(s) - set (abstract data type) , reliability (semiconductor) , mode (computer interface) , computer science , failure mode and effects analysis , control system , diagram , control theory (sociology) , reliability block diagram , control (management) , reliability engineering , state (computer science) , algorithm , engineering , fault tree analysis , artificial intelligence , power (physics) , physics , electrical engineering , quantum mechanics , database , programming language , operating system
A method of a reliability synthesis for a system with control loops is proposed by introducing a concept which we call a critical transition set. The set is an extended set of an exact failure mode and is important in that each occurrence of the system failure has to correspond to a mode in the set. This means that the system can be improved in such a way as to eliminate all the dominant modes in the set. First, the system diagram is obtained by connecting outputs of components to the inputs of succeeding components. Time delays are introduced in the feedback loops to represent the internal system state (memory). Then, the components are modeled by decision tables. The critical transition set can be obtained easily by simple tabular manipulations once the system failure is defined. Finally, the system reliability and availability improvements are made based on the set.