Stochastic analysis of a maintainable robot‐safety system with common‐cause failures

This paper presents reliability and availability analyses of a robot‐safety system having one robot and n‐redundant safety units with common‐cause failures. The system failure rates and the partially failed system repair rates are assumed constant, and the failed system repair time is assumed arbitrarily distributed. Markov and the supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Some plots of these expressions are shown.