Title :
Two Degree-of-freedom Control for Bi-level Positive Airway Pressure of an Obstructive Sleep Apnea Treatment System
Author :
Tsai, Ching-Chih ; Wang, Zen-Chung ; Chen, Chih-Sung
Author_Institution :
Nat. Chung Hsing Univ., Taichung
Abstract :
This paper presents a two degree-of-freedom control method for achieving bi-level positive airway pressure (Bi-PAP) of an obstructive sleep apnea (OSA) treatment system. After constructing a closed-loop DC brushless motor which is based on a microchip (dsPIC30F3010) drive together with a blower and an airway module, we develop a pressure control system for achieving Bi-PAP control. A mathematical model of the overall open-loop system is established based on the input-output data and its system parameters are sequentially determined using the recursive least-squares (RLS) approach. A two degree-of-freedom (DOF) controller, including a nonlinear feedforward controller and a feedback proportional-integral-derivative controller (PID controller) with gain scheduling, is proposed to maintain and follow the desired bi-level pressure setpoints. Through experimental results, the proposed control method is shown useful and effective in achieving bi-level airway pressure tracking.
Keywords :
brushless DC motors; closed loop systems; feedback; feedforward; least squares approximations; medical control systems; nonlinear control systems; open loop systems; patient treatment; pressure control; sleep; three-term control; PID control; bilevel positive airway pressure; closed-loop DC brushless motor; dsPIC30F3010; feedback proportional-integral-derivative control; gain scheduling; microchip; nonlinear feedforward control; obstructive sleep apnea treatment system; open-loop system; pressure control system; recursive least-squares approach; two degree-of-freedom control; Brushless motors; Control systems; Feedback; Mathematical model; Open loop systems; Pi control; Pressure control; Proportional control; Resonance light scattering; Sleep apnea;
Conference_Titel :
Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE
Conference_Location :
Taipei
Print_ISBN :
1-4244-0783-4
DOI :
10.1109/IECON.2007.4460146