TITLE:
Observer-Based Nonlinear Feedback Controls for Heartbeat ECG Tracking Systems
AUTHORS:
Witt Thanom, Robert N. K. Loh
KEYWORDS:
Heartbeat Model; Electrocardiogram; Nonlinear Control of Biological Systems; Input-Output Feedback Linearization; Observer-Based Nonlinear Control Systems
JOURNAL NAME:
Intelligent Control and Automation,
Vol.3 No.3,
August
30,
2012
ABSTRACT: The analysis and design of observed-based nonlinear control of a heartbeat tracking system is investigated in this paper. Two of Zeeman’s heartbeat models are investigated and modified by adding the control input as a pacemaker, thereby creating the control-affine nonlinear system models that capture the general heartbeat behavior of the human heart. The control objective is to force the output of the heartbeat models to track and generate a synthetic electrocardiogram (ECG) signal based on the actual patient reference data, obtained from the William Beaumont Hospitals, Michigan, and the PhysioNet database. The formulations of the proposed heartbeat tracking control systems consist of two phases: analysis and synthesis. In the analysis phase, nonlinear controls based on input-output feedback linearization are considered. This approach simplifies the difficult task of developing nonlinear controls. In the synthesis phase, observer-based controls are employed, where the unmeasured state variables are estimated for practical implementations. These observer-based nonlinear feedback control schemes may be used as a control strategy in electronic pacemakers. In addition, they could be used in a software-based approach to generate a synthetic ECG signal to assess the effectiveness of diagnostic ECG signal processing devices.