Diving is an important part of military and commercial purposes. The most advanced diving apparatus today is an eCCR, electrical Closed Circuit Rebreather. A rebreather works by recycling the exhaled oxygen that the diver breathes out.
This way minimal oxygen is used compared to other diving apparatuses. An eCCR utilizes oxygen sensors, which are not entirely reliable. Oxygen sensors measure oxygen pressure and can have many sources of errors in the sensors. These errors can lead to life-threatening oxygen pressure and are not detectable by the diver.
The purpose of this project was to simulate the eCCR system and be able to distinguish faulty sensors from correct sensors. The simulation was conducted in Matlab and Simulink. The sources of error on the sensors were a calibration error and an exponentially decreasing sensor. The methods used to test the simulation results were analyzing the frequency spectrum and time measurements of the sensors.
The result of the method was that the faulty sensors could be distinguished from a correct sensor, but only within a certain margin of error. It was also found that the method using the frequency spectrum was more reliable than using time measurements.
Ninni Hammarström, Magnus Erikson and Jesper Lidh
BTH Innovation Labs 