Sliding mode control for bilevel positive airway pressure: Advantages over PID control

A bilevel positive airway pressure ventilator (BPAP) is employed as a pneumatic splint for the upper airway in obstructive sleep apnea syndrome (OSAS) treatment. In this research we developed a cascade control scheme for the BPAP ventilator using a sliding mode control, generalized super twisting algorithm (GST). The gain design and the GST algorithm analysis are done using Lyapunov functions. A mathematical model of the human respiratory system and the BPAP ventilator were developed to test the GST control, analyze, and simulate the response of a person in normal conditions, during apnea, and treated with BPAP.