ROBUST CONTROL OF END-TIDAL CO 2 USING THE H ∞ LOOP-SHAPING APPROACH

Mechanically ventilated patients require appropriate settings of respiratory control variables to maintain acceptable gas exchange. To control the carbon dioxide (CO 2 ) level effectively and automatically, system identification based on a human subject was performed using a linear affine model and a nonlinear Hammerstein structure. Subsequently, a robust controller was designed using the H ∞ loop-shaping approach, which synthesizes the optimal controller based on a specific objective by achieving stability with guaranteed performance. For demonstration purposes, the closed-loop control ventilation system was successfully tested in a human volunteer. The experimental results indicate that the blood CO 2 level may indeed be controlled noninvasively by measuring end-tidal CO 2 from expired air. Keeping the limited amount of experimental data in mind, we conclude that H ∞ loop-shaping may be a promising technique for control of mechanical ventilation in patients with respiratory insufficiency.

[1]  H. W. Bode,et al.  Network analysis and feedback amplifier design , 1945 .

[2]  Lennart Ljung,et al.  System Identification: Theory for the User , 1987 .

[3]  G Matell,et al.  Computer simulation of a patient end tidal CO2 controller system. , 1989, Computer methods and programs in biomedicine.

[4]  Keith Glover,et al.  A loop shaping design procedure , 1990 .

[5]  E. Armstrong.  Robust controller design for flexible structures using normalized coprime factor plant descriptions , 1993 .

[6]  R. A. Hyde,et al.  H [infinity] aerospace control design : a VSTOL flight application , 1995 .

[7]  Richard A. Hyde,et al.  H Aerospace Control Design , 1996 .

[8]  R. Pearson,et al.  Block‐oriented NARMAX models with output multiplicities , 1998 .

[9]  D. Westwick,et al.  Identification of a Hammerstein model of the stretch reflex EMG using separable least squares , 2000, Proceedings of the 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (Cat. No.00CH37143).

[10]  R. Pearson,et al.  Gray-box identification of block-oriented nonlinear models , 2000 .

[11]  D. Gu,et al.  FORMULAE FOR DISCRETE ℋ∞ LOOP SHAPING DESIGN PROCEDURE CONTROLLERS , 2002 .

[12]  B. Lachmann.  Open Lung in ARDS. , 2002, Minerva anestesiologica.

[13]  M. J. Korenberg,et al.  The identification of nonlinear biological systems: Wiener and Hammerstein cascade models , 1986, Biological Cybernetics.

[14]  J. Newell,et al.  A feedback controller for ventilatory therapy , 2006, Annals of Biomedical Engineering.

[15]  Lu Wang,et al.  Nonparametric Hammerstein Model Based Model Predictive Control for Heart Rate Regulation , 2007, 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[16]  Stefan Mersmann,et al.  SmartCare®: Automatisierung klinischer Leitlinien / SmartCare®: automatizing clinical guidelines , 2009, Biomedizinische Technik. Biomedical engineering.

[17]  S. Rinnert,et al.  The value of ETCO2 measurement for COPD patients in the emergency department , 2011, European journal of emergency medicine : official journal of the European Society for Emergency Medicine.

[18]  G. Dumont,et al.  System identification and closed-loop control of end-tidal CO2 partial pressure in mechanically ventilated patients , 2011, The 2011 International Conference on Advanced Mechatronic Systems.

[19]  Anake Pomprapa,et al.  Predictive 3D Model Of CO2 Elimination For Optimal Pressure-Controlled Ventilation , 2012, ATS 2012.

[20]  G. Dumont,et al.  System Identification and Closed-Loop Control of End-Tidal CO$_{\bf 2}$ in Mechanically Ventilated Patients , 2012, IEEE Transactions on Information Technology in Biomedicine.

[21]  Berno J. E. Misgeld,et al.  L1 Adaptive Control of End-Tidal CO2 by Optimizing the Muscular Power for Mechanically Ventilated Patients , 2013, NOLCOS.