Diagnosis and Prognosis of Scrubber Faults for Underwater Rebreathers based on Stochastic Event Models

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Date
2011-06Author
Chang, Dongsik
Zhang, Fumin
West, Michael
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Show full item recordAbstract
Imperfect CO₂ removal mechanisms of CO₂ scrubbers
often lead to the existence of CO₂ in gas inhaled by a
diver from underwater rebreathers. This may cause CO₂ related
rebreather faults and subsequently would increase the risk of
human injuries. We introduce a stochastic model for three CO₂ related rebreather faults: CO₂ bypass, scrubber exhaustion,
and scrubber breakthrough. We establish the concept of CO₂ channeling that describes the cause of the faults and present
a CO₂ channeling model based on a stochastic process driven
by a Poisson counter. This helps us to investigate how CO₂ flow inside the rebreather is affected by CO₂ related faults.
Fault diagnosis/prognosis algorithms are developed based on the
stochastic model and are tested in simulation.