A Markov time related to a robot-safety device system (Q2386685)

A repairable system is considered consisting of a robot, a safety device, and two repairmen, one responsible for repairs of the robot and the other for repairs of the safety device. The state that the robot is operating while the safety device is repaired is called a risky state. The quantity of interest in the paper is the time needed to restore the system from a risky state into a safe state. Some theoretic results are derived and illustrated by an example.