Pressure Regulation for Oxygen Mask Based on Active Disturbance Rejection Control

Safe and reliable automatic pressure regulation for the oxygen mask is a primary consideration in an oxygen supply system (OSS). In order to enhance comfort of users, it is of significance to improve performance of the oxygen regulator. Based on analyses of the operation principle of electronic oxygen regulator (EOR), a new EOR is designed, where a proportional flow valve is adopted as the throttle valve, and an active disturbance rejection control (ADRC) strategy is applied to control the throttle valve. The external disturbances and the internal dynamics are estimated using an extended state observer. The dynamic compensation using a state error feedback in each sampling period reduces the plant approximately to an integrator tandem structure. Mathematical simulations are performed for the OSS to evaluate the control method compared with the proportional integral derivative (PID) control approach. The simulation and experimental results demonstrate that the ADRC can achieve precise pressure regulation with superior lower inspiratory resistance than the PID method, considering some environmental disturbances including the user's changing pulmonary ventilation. The work in this paper may be a reference for the EOR design.