Modelling and control of oxygen partial pressure in an underwater breathing apparatus with gas recycle

The paper deals with the control of oxygen partial pressure in rebreather systems. A new mathematical model describing the gas dynamics in the breathing system is developed and successively validated on experimental data. The model is consistent with the steady-state models commonly adopted for dive planning with rebreathers. We show with some example how our model can be used to design control action and to evaluate control system performance.