The Safety Assessment of Human-robot Systems : 3rd Report, On the Quantification of Consecutive Failure Logic

Abstract

Actual cases in which the output of a cut set depends on the sequence of occurrences of repairable basic events are shown in the FTA of human-robot systems. The necessity of quantification of consecutive failure logic is emphasized. Exact and approximate methods of calculating the existence probability and the expected number of occurrences of the output event are proposed. Input to the consecutive failure logic is assumed to consist of statistically independent, exponentially distributed and repairable basic events.